The COVID-19 pandemic has lifted a number of bioscience concepts from academic obscurity into everyday awareness. One erstwhile arcane concept is “flattening the curve” to avoid a steep spike of infection so that we do not overwhelm society’s capacity to deal with the cases that require medical attention. Another now familiar notion, that of “herd immunity”, postulates that once enough people are not susceptible to a pathogen, the infection rates drop, and the disease peters out. Flattening the curve is the immediate priority while herd immunity is needed to minimise long term impact.

At the time of writing (late April 2020), the measures taken around the world to restrict movement and person to person contact appear to be helping to flatten the curve, but these restrictions cannot be maintained indefinitely. Once the world comes out of lockdown, there is the very real risk of second and subsequent COVID-19 waves. One way to minimise the impacts of these waves is to adopt lifestyle practices that can help to strengthen peoples' immune systems to minimise infectious disease severity.

The practice Julie and I have adopted comprises of an integrated approach encompassing seven interlinked pillars of a healthy lifestyle:

1. A Wholefood Plant-Rich Diet
2. Frequent Movement
3. Sound Sleep
4. Effective Breathing
5. Psycho-Social Health
6. A Healthy Environment
7. Personal Empowerment

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I will introduce this approach in this article and list some of the practices I undertake to optimise my health. For a more personalised, practical, and in-depth understanding you can sign up for one of our participatory workshops or take part in one-one or small group coaching. 
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This and other articles that address SARS-CoV-2 and immune function are based on the logical assumption that improved immune function will help to limit the severity of infection from this particular virus. However, this cannot be definitively concluded until there is targeted research to confirm this underlying assumption.
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What we do know is those that suffer certain pre-existing conditions are much most vulnerable to COVID-19 than those who do not. A CDC report published in late March stated that 94% of all the people who have died from COVID-19 in the US to date had an underlying chronic condition such as type 2 diabetes, hypertension, cardiovascular disease, chronic lung disease, and obesity (CDCMMWR, 2020). The equivalent figure in Italy was 99% (COVID-19 Surveillance Group, 2020). The lifestyle interventions outlined in this article have been shown to prevent, arrest and even reverse the chronic conditions that serve as coronavirus welcoming mats.

The following diverse and consistent evidence base indicates that a whole food plant-rich diet is optimal for human health:

• Epidemiological studies of dietary pattern and health outcomes, e.g. studies on Seventh Day Adventists adopting a range of dietary journeys from omnivore to vegan and stations in between (Le and Sabaté, 2014) and studies of the world’s longest lived and healthiest populations – the “Blue Zones” (Buettner, 2010).
• Studies of human physiology and evolutionary biology that indicate that humans are primarily herbivorous animals (Mills, 2018; Warinner, 2013).
• Mechanistic studies looking at the impact of diet on physiology and biochemistry (Miller et al., 2009).
• The impact of dietary-based interventions on health markers, such as the cardiovascular disease (Ornish et al., 1990), prostate cancer (Ornish et al., 2005) and obesity, heart disease and diabetes (Wright et al., 2017).

​There is insufficient evidence to assert that a wholefood vegan diet is any healthier than a regime that  incorporates small quantities of animal products 1-3 times per week. This is why we use the term ‘plant rich’ rather than plant based. Our approach is summarised in the New Paradigm Health Wholefood Plant-Rich Diet Plate derived from the work of Fuhrman (Fuhrman, 2011), Popper and Merzer (Popper and Merzer, 2013), and Davis and Melina (Davis and Melina, 2014).

The categories can be broken down as follows:

• Sliver - Avoid: processed meat, non-organic animal products, GMO products, non-organic wheat products.
• 8% - Limit: Alcohol, eggs, dairy, red meat, poultry, fish, oil, sugar, processed food.
• 35% - Vegetables (30-50%): e.g. Kale, cabbage, broccoli, spinach, squash, peppers, onions, garlic, carrots, lettuce, cucumber, tomatoes.
• 20% - Fruits (10-30%): e.g. berries, apples, oranges, peaches, grapes, pears, bananas.
• 20% - Legumes (10-30%): e.g. Kidney beans, black beans, chickpeas, peas, lentils, soybeans, peanuts.
• 8% Nuts & Seeds (5-20%): e.g. Chia seeds, flax seeds, pumpkin seeds, walnuts, cashews.
• 30% - Starches (20-60%): e.g. whole wheat, brown rice, quinoa, potatoes, sweet potatoes.

​For an excellent summary of the power of plants to contribute to a healthy immune system, I recommend you read the article by Ocean Robbins - Smart Immunity: How Diet and Lifestyle Can Help You Stay Healthy in the Time of COVID-19. Robbins uses Joel Fuhrman’s handy acronym G-BOMBS to introduce the power of healthy foods to positively influence your immune system. G-BOMBS stands for greens, beans, onions, mushrooms, berries, and seeds. But remember, the power in the individual foods is manifested in the dietary pattern of which they are a part. There is little benefit in eating flax seed (ground not whole) for its omega-3s while guzzling down gallons of Coca Cola and binging on greasy kebabs. Superfoods are no longer super if they are part of a dietary pattern that minimises nutritional kryptonite. 

​Julie and I eat a wholefood vegan diet with no added sugar or wheat products and very little oil. We eat organic as far as possible.

​As might be evident, I prefer to get my nutrition from whole foods rather than from pills. Whole foods contain a complex of macro and micronutrients in a form our bodies are designed to absorb (Campbell and Jacobson, 2014). A focus on individual nutrients reflects a reductionist mindset prevalent in both the conventional and complementary health spheres. That being said, there can be instances when taking individual nutrients or other supplements is justified and an individualised regime may be required. Being a vegan, I take vitamin B12 (1,000 mcg, 3 times per week). B12 is produced by microbes that live in the environment and are ingested by animals. I also regularly take vitamin D (1,000 IU per day from October – April), quercetin (500 mg once per day) for gut health, and an algae-based source of omega 3 DHA (400 mg per day). At the first sign of an infection I take vitamin C to bowel tolerance and zinc (50mg per day).

​Our bodies are mostly water, so it is vital that we keep properly hydrated. According to a review study (albeit funded by the bottled water industry) there is evidence that not drinking enough may be associated with falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancer, urinary tract infections, constipation, dry mouth, cavities, decreased immune function and cataract formation (Jéquier and Constant, 2010). Here are some tips to maintain proper hydration

• Most people should take in 2-4l water/day including beverages. Your urine should be a light yellow colour. Ideal intake varies a lot depending on factors such as how energetic you are, temperature, humidity, etc. Those doing endurance activities in the heat can sometimes take in over 8l water/day.
• Drink water first thing: You can lose a lot of water at night especially if you are a nose breather.
• Drink water when thirsty: Thirst is a signal.
• Avoid soft drinks, ‘sports drinks’, energy drinks and fruit juice: Most are full of sugar, often contain caffeine and a variety of low level toxins.
• Drink water to compensate for alcohol: Most people know this but most of us don’t do it.
• Filter your water. Pure water is best but filtered tap water is often better for you than bottled water. And cheaper and better for the planet.

​I drink about 2.5 litres of liquid in an average day, about 1.5 litres is water and 1 litre is black tea and herbal teas. I drink a glass of red wine 3-5 times per week. 

​Eating is, of course, essential but it is nonetheless a stressor. This is evidenced by the fact that a large proportion of our immune system is contained in our digestive tract. Fasting can help to improve immune system function for a number of reasons including the following: inflammation of the digestive tract is reduced due to elimination of allergenic food (Salloum, 1999); normalised blood sugar levels, and enhanced immune cell activity (Hiramoto et al., 2008).

​Julie and I do regular short fasts of 18-24 hours, and quarterly 5-day fasts. While we are enthusiastic devotees of fasting, it cannot be overstated that for optimal benefits fasting must be part of a lifestyle that includes a healthy diet. Without this combination, we are prone to falling in the “detoxification trap” – indulging in periodic cleanouts, only to return to a toxic lifestyle. Such an approaches is akin to yo-yo dieting, high intensity exercise in an otherwise sedentary life, and the superfood and junk food combo outlined above. 

The oft-repeated mantra for good health – “eat less and exercise more” is quantitatively correct, but tells you nothing about the quality of what you are putting in your mouth, nor what you should be doing in terms of exercise. I prefer to focus on the word “movement” which encompasses both formal exercise and other types of movement. Paying attention to exercise alone may imply that all your body needs is short bursts of activity to offset long periods of sloth.

Unsurprisingly, researchers have found that the energy used in non-exercise activities dwarf the energy used in formal exercise for the vast majority of people (Shook, 2016).

A focus on movement encourages us to consider the importance of all of the physical activities we do throughout the day. Aboriginal people never formerly exercise but they are tremendously physically fit. Without the accoutrements of civilisation such as cars, dishwashers and home shopping delivery, aboriginal people, of necessity, have developed a daily movement regime in nature involving activities that are aerobic (talking pace), anaerobic (getting out of breath), mobility-related, and involve lifting heavy weights. We need to engineer a similar regime but one that is compatible with modern life.
That’s where OTMs (“Opportunities to move”) come in (Segar, 2015). What you focus on expands and awareness of the value of OTMs alerts us to the daily decisions that we (normally unconsciously) make about whether or not to move and how. Should I cycle or drive to work? Should I impersonate a circling vulture and always look for the closest parking spot or park further away? How can I reach for an object in a way that improves my range of movement? should I do yoga poses while the kettle is boiling, or should I slouch on the couch? Should I fidget at my desk or stay immobile? etc., etc.

But labour saving devices do exist and most of us are unlikely to embrace aboriginal living, so OTMs though necessary, may not be sufficient to maximise, strength, stamina, speed and flexibility; so most people need to do some formal exercise. The fact is that the best exercise for you is the exercise you will actually do, but here I want to single out the value of weight training in particular.

A great many people, especially women, are reluctant to use heavy weights (defined as a load that is close to your maximum) because they don’t want to “look like Arnold Schwarzenegger”. This is not a risk for most of us, men or women. Arnie and his ilk are “genetically gifted”, and spend hours working out. What I am advocating is within the reach of ordinary people.

Weightlifting helps to build bone density which decreases as you age. The higher the bone density, the less risk there is for fractures from falls. Fractures are a major cause of incapacity for the elderly and they are correlated with vulnerability to a range of morbidities. Weightlifting also improves flexibility as well as strength, so if you fall you have a better chance of breaking that fall and not fracturing. Weightlifting also helps to generate mitochondria – the body’s battery packs. More mitochondria equates to improved cardiovascular fitness.

The great news is that you can get the benefits of a strength-based conditioning from weight training for less than an hour a week using methods pioneered by Doug McGuff and John Little (McGuff and Little, 2009).

Exercise is a classic example of hormesis, or “good stress” – something that challenges the body which over-compensates and gets stronger (Mattson, 2008). A hormetic response is induced by pushing the body outside its comfort zone just enough. However, too much stress can overstretch the body’s capacity resulting in long-term breakdown.
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The relationship between exercise and immune system function appears to be subject to a j-shaped curve indicative of hormesis or the “Goldilocks effect” – not too much, not too little, but just right. So, engaging in moderate activity may enhance immune function above sedentary levels, while excessive amounts of prolonged, high-intensity exercise may impair immune function (Gleeson, 2007). The definition of “moderate” or “excessive” will vary according to the individual. 

​There is sound scientific evidence to support something that we have known intuitively all along – that getting out in nature is good for our health. Japanese scientists have studied the effect of “forest bathing” (visits to a forest for relaxation and recreation) on immune function compared to the equivalent activity levels in a city location (Li et al., 2008). The investigators found that the forest bathers exhibited a significant rise in immune cell number and function and a significantly decreased concentrations of adrenaline. In contrast, the “city bathers” showed no changes. The changes have been partly attributed to phytoncides (wood essential oils), released from trees. Phytoncides were detected in forest air, but there were only trace levels in the city. 

​My movement regime is daily OTMs with lots of fidgeting, daily 1-2 walks with the dogs, 20 minute weights sessions twice per week, 1-3 cycles at below aerobic threshold (roughly defined as "talking pace") per week, and ad hoc 10-20 minute yoga sessions. The exercise component of my movement regime takes an average of one hour per day.

​The invention of artificial light and a number of other developments have wreaked havoc on our sleep patterns. Most adults need 7-9 hours’ sleep per day but the average Briton gets only about six and a half hours (The Sleep Council, 2013). This is a huge issue and the importance of sound sleep for optimal health cannot be overstated. Specifically, there is a lot of peer reviewed literature demonstrating that sleep has a powerful effect on your immune response to viruses (Besedovsky et al., 2012; Cohen et al., 2009; Dimitrov et al., 2019).

Peoples’ sleep-related issues can be complex, and some people will need individualised support, but the following basic sleep hygiene tips can help in many cases:

• Stick to a sleep schedule. You cannot fully compensate for lack of midweek sleep with weekends of binge sleeping.
• Unwind before bedtime through calming rituals like reading, relaxing conversation, meditation, a bath or sauna, or listening to relaxing music.
• Use an alarm clock – to tell you to get ready for bed. Don’t use one to get you up except as a transitional measure to regularise waking up times, or on the odd occasion when you need to get up especially early. If you do need an alarm, do what you can to avoid the snooze button.
• A healthy diet can improve sleep (St-Onge et al., 2016).
• Being physically active increases sleep quantity and quality especially in the middle and old ages, but strenuous exercise less than 2-3 hours before bed is not advisable.
• A hot bath before bedtime can help sleep.
• Don’t stay in bed if you cannot sleep. If you do not sleep within twenty minutes or so, do something relaxing that does not involve screens until you are tired. Otherwise your anxiety about failing to get asleep may make it harder to fall asleep.
• Turn your bedroom into a sleep sanctuary
  • Keep your room cool
  • Keep your room dark
  • Remove phones, TVs, laptops, tablets
  • Have a comfortable bed with clean sheets, create an uncluttered environment, add a few houseplants to improve indoor air quality, add an essential oil burner and burn oils such as lavender and jasmine, create an alter if you are so inclined. However, be careful about burning incense as many incense sticks contain toxic chemicals
• Avoid certain things and curfew others
  • Nicotine – avoid
  • Caffeine – avoid or curfew
  • Alcohol - avoid or curfew
  • Large meals and drinks - curfew
  • Screen time – curfew. Minimise watching the news or other programmes that are likely to stimulate adrenaline production.
  • Work – curfew.

​I sleep 7 to 8 hours most days and go to bed at about ten o'clock most evenings. We follow the sleep hygiene tips outlined above, but do not always keep to the screen curfew before bedtime. However, if we do watch TV close to bedtime, we will be wearing our funky yellow-tinted specs which block blue (‘daytime’) light – it’s one of life’s little compromises. 

​It is estimated that we take more than seventeen thousand breaths a day, usually without even being  aware of a single one. Becoming more aware of our breathing and harnessing this awareness on a regular basis can be immensely therapeutic. There are endless breathing techniques, notably from the yogic tradition, but here I will focus on three easy to learn practices that can help us to step back from life’s daily dramas.  

This simple technique can be used anywhere, anytime and anyplace and is a great instant stress reliever (Davidji, 2017). It comprises of one or more rounds of breathing in for a count of four, holding your breath for a count of four, breathing out for a count of four, and holding your breath for a count of four. Repeat as necessary. 

​For more details, see my article: Cultivating Stillness: Control, Alt, Delete for your Bodymind.

Developed in Russia by Prof. Konstantin Buteyko, the Buteyko Method comprises of reduced-volume breathing and breath holding. It has been shown to be effective for the management of asthma, with people able to substantially reduce medication with no deterioration in their asthma control, although no studies have demonstrated objective changes in lung function (Rosalba, 2008). The technique emphasises nasal breathing which is is likely to increase nitric oxide (NO) levels. NO influences many physiological processes including bronchodilation, vasodilatation, tissue permeability, immune response, oxygen transport, neurotransmission, insulin sensitivity, memory, mood, and learning.

​For a practical demonstration of Buteyko breathing, check out the video below.

This system has been developed by the eponymous Wim “the Iceman” Hof – a Dutch eccentric with the look of a leprechaun, the enthusiasm of a young child, and the delivery of a stand-up comedian. His achievements include setting world records for the length of time for swimming under ice, and the fastest half-marathon ran barefoot on ice and snow. He has reached the top of Mount Kilimanjaro in two days wearing only shorts and shoes, and he ran a full marathon in the searing heat of the Namib Desert without water – thus proving his resilience at both ends of the thermometer. A wee word of warning: Wim Hof has been doing this stuff for many years. I am recounting his feats as a testimony to the power of the body-mind, not as an encouragement to others to attempt to emulate or surpass Wim, unless they build up gradually and have full medical backup.

The Wim Hof Method (WHM) comprises of three pillars: breathing, cold exposure and meditation. Here we focus on “Wim Hof breathing”. Drawing heavily on yoga practices, notably Tummo or Chandali Yoga, Wim Hof breathing comprises of cycles of hyperventilation followed by breath holding (hypoventilation) which helps us to resist the cold (Carney and Hof, 2017). The method has been subject to scientific scrutiny in which the investigators found that trained group were better able to fight off infection than an untrained control group (Kox et al., 2014).  The essence of the method is very simple to learn from the free miniclass available on Wim Hof’s website.

Before exercising I use Wim Hof’s 11 minute guided breathing session (from the video below) as a way to increase my energy levels. For the rest of my day I use nasal breathing with periodic Buteyko exercises and sixteen second breaths as necessary.

There are many kinds of stress, but they all boil down to physical, chemical, or psychosocial stimuli that are present in too high a dose, too low a dose, or are stimuli that are too new for the body-mind to absorb. Novel compounds such as synthetic pesticides and plastics come into this category as do substances such as mercury and asbestos, which occur naturally but to which we would not have been regularly exposed during our evolutionary history. The body is constantly subjected to stresses, for example, air and water pollutants, potentially stressful events, processed foods, and electromagnetic radiation. But we have mechanisms to deal with stresses/toxins including a well-functioning immune system. The capacity of the body to deal with stresses/toxins can be compared with a bucket. As long as there is capacity in the bucket the body does not become diseased, but if there is more stress/toxicity than the bucket can hold a disease will emerge. Disease emerges once a threshold is crossed.
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In common parlance, people use the term stress to refer to psychosocial stress - anything that translates into a perceived threat to our social status, social esteem, respect, and/or acceptance within a group; threat to our self-worth; or a threat that we feel we have no control over. There is a plethora of literature on the effects of psychosocial stress on the immune system and its effects on a diverse range of chronic and infectious disease processes and outcomes (Campos-Rodríguez et al., 2013).
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Rather than attempting to summarise the vast literature, I will outline some simple practices that can help to manage psychosocial stress – a daily gratitude practice, Emotional Freedom Techniques (EFT or Tapping) and mediation. One valuable stress management modality - mindful breathing is summarised above. 

Humans are hard-wired to pay attention to threats. This has had survival value for much of our existence as a species, and it still has to some extent. In ancient times it would not have been to your benefit to admire the graceful feline form of sabretooth tiger which sought you out for its supper. Rather, you needed to focus on its bad intentions and turn tail as fast as possible, or hurl a spear into the space between its eyeballs. And in modern times, the best attitude to that unexpected email with news of your inheritance from your lost late uncle Eustice is to distrust and delete rather than trust and transact. So “negativity” is necessary, but it can lead to chronic stress if it perpetually casts a shadow over the positive side of the coin.

There is a great deal of evidence that a daily gratitude practice has powerful physical and psychological benefits (Emmons, 2008). And, the more we focus on what we are grateful for the more we find things to be grateful for. What you focus on expands.

Julie and I have a simple morning and evening gratitude practice in which we alternately state three things that we are grateful for. They can be large things such as the beautiful planet on which we live, or everyday experiences such as having a nice walk with dogs.
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Despite its apparent simplicity, it is possible to mess up a gratitude practice and I speak from experience. When we started the ritual in April 2013, I only focused on overtly positive things but steered clear of the silver linings that hide in every cloud. This engendered denial and frustration. I write about this experience in the article How I messed up my daily gratitude practice - Walking the tightrope between expressing appreciation and kidding ourselves. 

Thanks to my wife Julie, who is a Certified EFT Practitioner, I learned the basics of tapping and, have been using EFT for some time when I felt emotional blockages, large or small. Tapping your fingers on acupuncture points on the face and body calms the amygdala (the part of your brain that triggers your fight or flight response) and helps energy to flow freely throughout the body. Tapping has been shown to provide effective relief for a myriad of issues such as anxiety, depression, obesity, high blood pressure and chronic pain.

The classic EFT process involves tapping nine acupuncture points in turn and saying (aloud or to yourself) “even though I have this problem” [insert problem here], “I love and accept myself.” Following this ‘set up statement’, you come to name the problem, explore its root cause and find your own solutions while you are in a resourceful state, rather than sitting or lying passively. Tapping can be done on your own, but it is better to work with a qualified therapist if you are a beginner or have complex issues to deal with. Tapping is easier to conceive of when watched rather than read about so I recommend that you consult the short YouTube video linked to below for a clearer idea of what it is all about and how to do it.

​Meditation has moved from the margins to the mainstream in recent years. Like breathing practices, there are diverse approaches to meditation. Many of us who have been brought up in the west struggle with meditation. This is not surprising given the nature of our upbringings with a focus on logic and the material world. I am by no means a meditation master but find the following technique I call decoupling your trains of thought to be useful. This technique was introduced to me by Neuro-linguistic programming (NLP) expert, life coach and “head fixer” Ali Campbell. I call it Decoupling Runaway Trains of Thought. 

Ali describes this form of meditation “for people who suck at enlightenment!” as the single most powerful exercise he has done to improve his life. That statement certainly made me sit up and listen as it comes from a man who has a deep understanding of a rich smorgasbord of life-changing techniques. Below is a summary of this simple but very powerful exercise. 

• First find a reasonably quiet place. 
• Set a timer for five, ten or fifteen minutes. 
• Close your eyes if it is safe to do so. 
• Allow a thought to come to you as it surely will. Acknowledge it as a thought about a thing. For example, oh there’s a thought about washing the dishes, do not attach any meaning to this thought – there is nothing you can do about the situation at this time.
• Let this thought go, and another thought will come to mind. 
• Acknowledge this thought as a thought about a thing and let it go. 
• Keep with this process until your time is up.

​When you first start doing this you will probably find that the thoughts come thick and fast. Ali Campbell likens it to a dam bursting and unleashing a torrent of thoughts. But over time you will find that the thoughts flow more slowly, as if you are sitting by a riverbank observing the thoughts gently flowing by. 
 
In addition to our daily morning and evening gratitude practices, Julie and I meditate every morning for about ten minutes.

​Nobody lives in a vacuum and we are all influenced by the environment in which we live. So the link between environment and health should be self-evident, yet it is often ignored. In this section I introduce the topic of toxins found in our indoor and outdoor environment and explore the benefits of hot and cold exposure for the immune system.

Many a substance has followed a familiar journey from being labelled as harmless to being declared to be toxic, via what I have named “The Schopenhauer Sequence”, after Arthur Schopenhauer’s famous quote on the nature of truth. The sequence from ridiculous to self-evident via opposition has been repeated time and again for a long and growing list of substances, which have transitioned from apparently benign to being banned, restricted, heavily taxed, or plastered in health warnings. Substances that have completed the sequence include lead, asbestos, DDT, PCBs, BPA, and of course tobacco. Some are in still in the violently opposed state. These include mercury in dentistry; aluminium in cookware, antacids, antiperspirant and vaccines; and glyphosate in pretty much everything we eat and drink (Myers et al., 2016). Currently in the ridicule stage, with a mix of violent opposition thrown in for good measure, is electro-magnetic radiation, in particular 5G (Davis, 2019).

The above discussion refers to individual substances, but in the real world pollutants are likely to act synergistically, but synergies are almost never tested for. With hundreds of new chemicals being added to the environment every year, this testing gap is to be expected.

In the absence of adequate testing, examination of synergies, and long term monitoring, we are all unwitting participants in an uncontrolled natural experiment. Because so much stuff is being introduced at once it is very difficult to unravel cause and effect. In such circumstances I rely upon the precautionary principle – “guilty until proven innocent”. The precautionary principle states that when human activities may lead to unacceptable harm to humans or the environment that is scientifically plausible but uncertain, actions shall be taken to avoid or diminish that harm. What this means for me in practical terms is that I will let the Schopenhauer Sequence play out, but in the meantime, I will use natural personal care and cleaning products, filter my drinking and washing water, eat organic food as far as possible, and use a wired Internet connection. 

As discussed earlier, we can tolerate a bit of toxicity and according to the toxic bucket or total load model of disease, disease emerges when our exposure to toxins exceeds our ability to mitigate this exposure. The lifestyle strategies outlined in this article are designed both to minimise exposure and to mitigate toxicity, a central component of which is optimising our immune system.

For centuries, hot and cold treatments have been advocated for health, hygiene, social, and spiritual purposes. The potential for health benefits of heat and cold is congruent with the principle of hormesis. One of the most studied modalities is sauna bathing (Hussain and Cohen, 2018).  Numerous beneficial effects have been suggested, including a reduction in the risk of developing certain chronic or acute respiratory illnesses (Kunutsor et al., 2017).
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Another simple hot-cold treatment is a contrast shower in which you flip between hot and cold. A hot to cold shower is one of the pillars of the Wim Hof Method. Most people will be able to gradually adapt to longer periods of cold, but anybody with heart disease should exercise caution regarding cold exposure. It is advisable for this group to consult their doctor if contemplating cold baths, open water swims in winter, contrast showers or similar practices. 

I meditate in our homemade near infrared sauna for about ten minutes every day and have a contrast shower of two sets of one-minute hot, one-minute cold. I know it could be a bit longer, but I don’t want to waste water!

​The healthy living approach we promote at New Paradigm Health is one that is based on personal empowerment – where each individual develops their own set of lifestyle practices that facilitate optimal health in a manner that is congruent with their unique nature and circumstances. These practices must be based on an understanding of their fundamental human needs and a knowledge of where their personal power lies. Without these foundations, people are prone to be blown off course by events, trends and the well-intentioned and sometimes not so well intentioned opinions and advice of others. 

Tony Robbins’ six human needs framework provides a simple, powerful and intuitive framework for assessing our dispositions. I have used this framework to understand my own aptitudes and those of the people I work with as part of a strengths-based approach to personal and organisational development.
Tony Robbins has built on the work of John Burton and Abraham Maslow to develop human needs psychology. In essence, Robbins believes that everybody’s actions are driven by the need to fulfil one or more of six basic human needs. By definition, these are needs that we all share, but everybody is unique, so we do not value all our needs equally. Different people will emphasise different needs and this emphasis often shifts as we go through life.

The six fundamental human needs are as follows:

1. Certainty – that things will unfold as imagined.
2. Uncertainty – that life will serve up its share of variety.
3. Significance – the sense of being special or unique.
4. Love and connection – the feeling of togetherness or intimacy.
5. Growth – the feeling that we are making progress.
6. Contribution – that we are part of something bigger than ourselves.

I unpack these each of these needs in my article - Why we Think and Act the Way we Do: The Six Fundamental Human Needs as the Basis for our Unique Dispositions.
Understanding our human needs helps us to know which needs we habitually meet, which needs are not being met, which needs we want more of, and conflicts and trade-offs between meeting some needs at the expense of others. This understanding also helps us in our relationships of all kinds as we become less judgemental by acquiring a fuller understanding of the factors that motivate other people’s aptitudes, attitudes and actions.
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You can assess your human needs with this online test devised by Chloe Madanes who has worked extensively with Tony Robbins to advance the thinking in the field. The results include detailed information on how your primary need and top two needs can serve you or hold you back.

​I love the Serenity Prayer – or at least the three lines which I know, as made famous by Alcoholics Anonymous:

​Grant me the serenity to accept the things I cannot change
The courage to change the things I can
And the wisdom to know the difference

In terms of understanding your place in the world, it is critical to know what circumstances are under your control, what circumstances you can directly influence, and what circumstances you can neither control or influence despite the fact that they are cause for concern. 

This model can be visualised in terms of circles of control influence and interest. Only one person stands in the circle of control – yourself. However, you do have some influence on others with whom you interact, just as they have influence on you. Finally, there are others whom you cannot directly influence whose actions may give you cause for concern. This is a concept used in the Outcome Mapping system for project planning, monitoring and evaluation – a system I find very useful and use extensively in my work.

In terms of living in alignment with your values, it is advisable to place most effort in the spheres of control and influence where you are best placed to make a difference. Of course, as is clear from its name, you are still interested in the sphere of interest/concern, but your ability to directly affect change in this sphere, at least in the short term, is limited.

Knowing where you stand helps to provide you with the certainty you need to face life’s challenges regardless of how much influence you may or may not have on others and in the face of concern about a world that does align with your deepest held values. Most people do not have the power to reverse the endless stream of doom and gloom that is the 24-hour news media, nor to affect entrenched power structures in the immediate term; but they do have considerable power over what they put in and on their bodies, what they put their bodies into, and what they put their bodies through. Being the change you want to see in the world is powerful and helps to displace fear with focus. 

​There are some really useful maps and charts that help us to make sense of the patterns of coronavirus occurrence and severity. The most familiar are variations on the theme used by the WHO in their daily Situation Reports. There is also the excellent COVID-19 Dashboard from the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU), and I love the COVID-19 GIFs from World Mapper. The map below, used in an excellent Newsweek article, is representative of the typical maps we see every day. They provide useful summaries but do not capture the patterns as they unfold over time. 

However, I wanted a one-stop shop - something that represented the daily progress of the pandemic over the planet, but I could not find anything that fitted the bill. The WHO maps could not, because they have used different scales throughout the infestation. They have also represented totals in terms of numbers per country rather than incidences per capita. This can exaggerate the relative severity of the situation in large and/or populous countries (notably India and Russia). This is a bit like saying India with a total GDP of $US2,800 billion is a richer country than Ireland whose GDP is $US381 billion.

So I decided to make the charts I was looking for. I also added a ‘thermometer’ to keep track of seven-day mortality as a way of gauging the effectiveness of disease management efforts at the global scale. Some people have asked why the red column on the left sometimes go down. That's because it represents the total numbers of deaths from COVID-19 during the previous seven days. When this figure drops consistently it will show us that we are really getting on top of the pandemic at the global scale.

I have used reported deaths rather than incidences as death represents the ultimate hard endpoint, and the reported incidences data strongly reflects the intensity of testing. At the time of writing (mid-April 2020) Germany, for example, has a higher number of COVID-19 cases than UK but a lower level of mortality. All this being said, it needs to be recognised that there are still great imperfections in the data on causes of death, as countries vary hugely in their detection and reporting capacity.

​Here is my first offering. 

​Below are a few of my take home observations based on this time series.

• January and February were ‘lost months’ for early COVID-19 action in Europe and USA, when decision-makers may have been lulled into a false sense of security by the (predictable) slow growth in cases in the early phase of exponential growth.
• There appears to be a relationship between climate and COVID-19 severity, with both warmer and cooler parts of the world having relatively lower mortality – the ‘viral Goldilocks effect.’ However, the climate-mortality link is far from proven, and other factors also come into play. Economic development levels appear to be important if we compare the relatively higher mortality figures of Australia and some South American countries with those for many parts of sub-Saharan Africa. Higher levels of economic development may be associated with other factors such as increased travel and more hours spent in air conditioned environments.
• At the time of writing (13 April), COVID-19 deaths are rising globally at an alarming rate, and we will need to maintain our individual and collective efforts if we are to minimise future mortality increases.

 ​I will update these videos every month. Here is the second offering. In addition to charting the trajectory of the pandemic, I ​explores some of the possible reasons for the observed patterns - climate/UV, smoking, air pollution, mobility patterns, age distribution, management practices, and dubious data.

Although not doing everything I want, the best mapping resource I have found for COVID-19 and a variety of other topics is from Our World in Data. With thousands of free, open access and open source  charts covering a range of topics including health, education, and the environment, it is a goldmine. They present the COVID-19 data in useful and interactive ways not seen on other websites. 

All free: open access and open source. An example chart is shown below.

“My job is not to scare you out of your wits, it's to scare you into your wits.”
Professor Michael Osterholm - epidemiologist and director of the Center for Infectious Disease Research and Policy at the University of Minnesota.

​Like all crises, the coronavirus pandemic ushers in opportunities and threats. It is a powerful reminder of the power of infectious disease to spectacularly derail business as usual, and the urgent need to develop systematic and proactive strategies to manage to infectious diseases. A danger is that the crisis will be seen in isolation from other existential threats, all of which are intimately and inextricably dependent on a complex web of planetary life support systems. If these crises are treated in isolation, then it is likely that we will continually operate in reactive mode, while root causes remain unaddressed. In this article I examine some of the root causes of disease epidemics and the links between these diseases and some of the principal forces that undermine planetary health – climate change, mass animal rearing, biodiversity loss, and pollution. I also touch upon the links between infectious and chronic disease, and acknowledge the critical role of sustainable economic development in disease management. To build resilience in our planetary life support systems I propose a series of mutually supporting recommendations in seven areas: personal health, climate change, animal agriculture, biodiversity restoration, pollution, infectious diseases, and science and public communication.

Click here for a PDF version of the article

Here are a few selected quotes from the great and the good that illustrate our oh so human fallibility when it comes to the precarious process of prediction:

• In 1943, Thomas J. Watson, long-serving chairman and CEO of IBM declared, “I think there is a world market for maybe five computers.”
• In 2004, Bill Gates confidently predicted that, “Spam will be a thing of the past in two years’ time.”
• In 1962, Sir Macfarlane Burnet, Nobel laureate in medicine, stated, “One can think of the middle of the 20th century as the end of one of the most important social revolutions in history - the virtual elimination of the infectious disease as a significant factor in social life."

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​With the benefit of hindsight, it is easy for us to roll our eyes when it comes to the mistakes of others. But futurology failures listed above are merely examples of the kinds of mistakes that we all continually make. Our poor powers of prediction are compounded when it comes rare and catastrophic events. 
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Every year since 2006, hundreds of leaders from business, government and non-profit communities participate in the annual Global Risks Perception Survey. The results are compiled in the World Economic Forum Global Risks Reports. The reports for 2007-2020 rank global risks in terms of the likelihood that they will occur and their impact on the global economy should they occur. The perceived risk of pandemic disease always rise in the charts in the wake of a previous epidemic – H5N1 (bird flu) in 2006, H1N1 (swine flu) in 2009, Ebola in 2014, Zika in 2016. The survey for the 2020 report was conducted from 5 September to 22 October 2019 before the novel coronavirus infectious disease (henceforth Covid-19) emerged in Wuhan China in December 2019.  I am writing this in March 2020 from a world in lockdown and standing on the precipice of a cocktail of crises. From this perspective, there is little doubt that disease pandemics will top the 2021 charts. But, between major epidemics the perception of risk falls, only to rise again when the next epidemic occurs. This reflects our individual and collective event-driven cycles of panic and amnesia.

​The above observations are not meant as a criticism of the survey participants, whose responses reflect a natural  “immediacy bias”, to which all people are prone. This tendency is driven by our evolutionary history throughout which those who responded best to urgent threats to life and limb were the ones who survived and reproduced. Better to flee right now from the sabretooth tiger who wants to have you for dinner than to contemplate the possibility of being infected by a yet to be identified disease at an indeterminate time in the future. Despite the fact that most of us in the modern world rarely encounter urgent life or death situations our brains are still programmed to prioritise what we perceive to be immediate threats. Neither is the current focus on pandemics, a reflection of immediacy bias, meant to minimise the importance of the other economic, environmental, geopolitical, societal, and technological threats identified: threats as apparently diverse as climate action failure, weapons of mass destruction, cyber attacks, illicit trade, and biodiversity loss. They are all important and where they are ranked will vary according to time, place and perspective. 

​Since Covid-19 has exploded into our collective conscious, many people have fallen into the trap of defending their particular perspective by stating or implying that the ‘their issue’ is more important than Covid-19 in the grand scheme of things. For instance, some activists have argued that climate change poses a greater threat to humanity than Covid-19 – a sentiment I agree with. However, I disagree with how such sentiments are being communicated for one main reason:  by highlighting the primacy of any one issue we are creating distinct silos which pit one issue against another in a competitive struggle for airtime, awareness and funding. Demarcating separate issues is necessary but it is important to embed these issues in a framework of common root causes that underpin our global interacting crises. Without a more integrated approach to our interdependent crises, we will become trapped in a continual game of “Crisis Whack-a-Mole” in which chance, whim, preference, and events drive knee-jerk reactions, with funds constantly shifted from yesterday’s issue du jour to today’s in lockstep with the panic-amnesia cycle.

This article situates the rising threat of global pandemics in its wider context of planetary health, to illustrate that in nature everything is connected and we cannot think or act in silos if we are to make the world a better place for humanity and the planet upon which we depend. I will explore some ways in which the impacts of infectious disease are exacerbated by chronic disease, climate change, mass animal rearing, biodiversity and habitat loss, and pollution in order to encourage a holistic or “planetary health” approach to sustainable development. This approach means looking at each threat as part of a wider system, exploring links between components of this system, and proposing solutions that strengthen resilience – the ability to bounce back after a setback. Critically, measures that build resilience in any one component, should not undermine resilience in any of the other components of what is a single planetary system.

But before exploring these components and their connections with infectious disease, I will list some reasons why there has been a rise in global disease epidemics in modern times, and introduce the “Stress Bucket” as a model for personal and planetary health and resilience.

​This is really a two part question: first, has there actually been a rise in global epidemics in recent history, and if this is the case, what has caused this rise?  The answer to the first question is a resounding yes. The most destructive epidemic ever in terms of lives lost was the 1918-1919 Spanish flu (which, despite the name, probably originated in a pig farming operation in Kansas). Since then there have been three major flu epidemics – the 1957 H2N2 Asian flu, the 1968 H3N2 Hong Kong flu, and the 2009 H1N1 swine flu; two coronaviruses - SARS (Severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome), which burst on the scene in 2002 and 2012 respectively; and Ebolavirus from 1976, with its most destructive manifestation in 2014. And it is easy to forget about diseases that have become endemic like HIV/AIDS which has probably been around for over a century but only grew explosively in the 1980s, and vector-borne diseases such as Zika, dengue, yellow fever, and chikungunya viruses, which have had major outbreaks in the past few years. 
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Public health professionals and those familiar with the workings of the natural world have been sounding the alarm for some time, warning, in the manner of seismologists, that we are due “the Next Big One” anytime soon - it has always been a question of when rather than if. In the words of Bill Gates:
 
“If anything kills over 10 million people in the next few decades, it’s most likely to be a highly infectious virus rather than a war. Not missiles, but microbes. Now, part of the reason for this is that we’ve invested a huge amount in nuclear deterrents. But we’ve actually invested very little in a system to stop an epidemic. We’re not ready for the next epidemic.”

Now, to the second part of the question - what has caused the rise in epidemic diseases today? In short, pathogens multiply at a stratospheric rate compared with people. Most humans live for 20 plus years before they reproduce whereas pathogens can replicate in minutes or hours under the right circumstances. Every generation provides the pathogen an opportunity to evolve in potentially destructive ways. We are increasing our encounters with pathogens and thus providing them with a multitude of opportunities to cause us harm. We do this through the destruction of nature, by warming the planet, by keeping thousands of farm animals in cramped together in unhygienic conditions, by misusing antimicrobial drugs, by the world’s growing population, and by increasing the volume and speed of movement of people and products at the local, regional and global scale. Further heat is applied to the pathogenic melting pot by the burden of pollution and chronic diseases which help to compromise people’s immune systems thereby providing the perfect conditions for infectious disease to take hold and prosper.

​Anybody who has attended one of my health-related talks knows that I like to use the analogy of the “stress/toxic bucket” when conceptualising the development of chronic disease. The body is constantly subjected to stresses of all kinds; for example, organic and inorganic toxins, potentially stressful life events, the news which always seems to be depressing, processed foods stripped of nutritive value and loaded with synthetic additives, poor sleep quality and quantity, mold, infections, and drugs – both recreational and pharmaceutical. But the body has diverse and effective mechanisms to process stress/toxins. In fact, an appropriate amount of stress can be a good thing. Think of exercise, which exerts its beneficial effects by pushing the body just a little beyond its current limits in order to stimulate a more than commensurate recovery - a phenomenon known as hormesis. The capacity of the body to deal with stress can be thought of as a bucket. As long as the bucket has spare capacity the body does not become diseased, but if there is more stress than the bucket can hold, the stress overflows and a disease emerges as a threshold is crossed. The spare capacity of our stress bucket represents our resilience, This can be measured by a vast array of biomarkers including some commonly used metrics such as blood pressure, blood cholesterol and triglycerides, kidney function, blood sugar, inflammation markers, etc. 

​In a similar vein, the planetary systems that provide the ecosystem services that underpin our survival can be conceived of as the planetary toxic bucket. These systems include the maintenance of global, regional, and local climate, soil conservation, biodiversity conservation, biogeochemical cycles (the water cycle, the oxygen cycle, the carbon cycle, etc.), and flood protection.

Human pressures on every aspect of the environment have resulted in a compromised and overflowing planetary stress bucket, leading to a host of multiple planetary comorbidities, such as the shrinking of the ice caps and rising sea levels, more frequent and extreme weather, galloping desertification, epoch-defining species extinctions, habitat destruction and fragmentation, unprecedented biological invasions, and burgeoning disease epidemics.
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We urgently need to redouble our efforts to restore our planetary life support systems if we are to navigate our way out of our interconnected crises in an orderly fashion. Half measures are not enough to restore the planet’s resilience and will result in a panicked stampede for the limited seats on board the illusory lifeboats constructed under the hubristic notions that we can invent ourselves out of the laws of nature or somehow concoct a Planet B.

​There are many ways in which climate change can, directly and indirectly, impact the frequency and severity of infectious diseases. One of the most obvious ones is through an increase in mosquito populations - those flying syringes that transmit a host of annoying, debilitating or devastating diseases to humans and other animals. A great example to illustrate this phenomenon comes from the Big Island of Hawaii. The Big Island is essentially a giant volcanic cone with temperature falling as you go higher up the cone. A particular mosquito species, the southern house mosquito (Culex quinquefasciatus) is an introduced species that transmit the pathogen that causes avian malaria, one of the main reasons for extinction and population declines of native Hawaiian birds. Until recently, cool temperatures had limited mosquitoes numbers in the higher parts of the island, thus providing a high altitude bolt hole for the birds. Rising temperatures are allowing the mosquito to spread to higher ground ushering in avian malaria, forcing the birds into ever-shrinking sanctuaries, and ramping up the probability of global extinction of these precious jewels that are found nowhere else on the planet. 

​Those who don't care about the plight of a handful of Hawaiian bird species may change their tune if they thought of these birds as being the canaries in the climate change coal mine whose fate may become our fate with increases in mosquito habitat, along with other attendant consequences of climate change such as rising sea levels, mass migration, increased flooding and extreme weather events, all of which can facilitate the spread of disease. 

“Our most dangerous adversary will not originate in the tribal areas of Afghanistan or some other remote place. It is everywhere man and animal live in close proximity.” ~ Michael Osterholm

Approximately three quarters of emerging human infectious diseases are caused by zoonotic pathogens – disease causing agents that can spread between humans and other animals. Transmission from wild animals represents one major risk pathway for the spread of zoonotic disease and intensive animal agriculture represents the other.

The world’s human population of 7.8 billion and counting is dwarfed by the billions of animals we hold captive in barbaric conditions to satisfy our lust for cheap and tasty meat. At any one time the world population of chickens numbers about 20 billion. With around ten generations per year this translates into 200 billion separate animals alive (and dead) in a single year. That’s a lot of incubators for emerging diseases. Pigs, of which about 400 million are slaughtered each year, are often confined in close proximity to intensive chicken rearing units. Pigs can be simultaneously infected by both human and bird influenza viruses, but they don’t show many symptoms, so they are rarely tested. Undetected, unaffected and in close proximity to birds and humans, pigs provide a veritable witches’ cauldron for shape shifting viruses of pandemic potential. 

Another way in which intensive animal agriculture increases disease prevalence is through the massive use of antibiotics where they are administered to prevent and treat infection and to stimulate growth. About 70% of antibiotic use in the developed world is for intensive agriculture and the figures for the rest of the world are likely to be similar. The use of antibiotics in agriculture along with their overuse and misuse in health systems worldwide combine to drive the growth of global antibiotic resistance. Many sober commentators are warning of an impending post-antibiotic era in which diseases such as tuberculosis, plague, syphilis and cholera, hitherto kept in check, will re-emerge as global scourges, and in which routine surgical procedures will pose life or death risks. In case you think this is alarmist hyperbole, growing antibiotic resistance is already leading to thousands of deaths through the rise of “superbugs” such as C. diff (Clostridium difficile) and MRSA (Methicillin-resistant Staphylococcus aureus). 

Our lust for meat is fuelled by the myth that human beings require animal protein to be healthy. The reverse is actually the case, with a whole food, plant rich diet being the best diet for longevity and minimisation of disease risk as illustrated by a plethora of studies. The people of the “Blue Zones”, those parts of the world with a disproportionate number of centenarians (people who live long and die short) all eat diets which are low in animal products and high in vegetables, whole grains, fruits, nuts, and beans. A whole food, plant-rich diet is also shown to protect people from the west’s biggest chronic disease killers such as cardiovascular disease, diabetes, cancer, liver disease, kidney disease, COPD and even depression. Less attention has been focused on the fact that those eating this diet and undertaking other healthy lifestyle habits such as sufficient sleep, stress management, and frequent movement have had access to supportive communities are also less vulnerable to infectious diseases.
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So eating low on the food chain is good for the planet in terms our carbon footprint, works for animal welfare, reduces the potential development of deadly zoonoses and increases our resilience in the face of infectious diseases. What's more the food is delicious, once you’ve kicked your meat addiction and learned some creative cookery. 

“Zoonotic or agricultural bridging of novel pathogens from domestic and captive wildlife needs urgent attention, along with attention to the human appetite for meat. This approach is easily achieved for coronavirus threats—e.g. by substantially reducing the trade of risky species of wild caught animals for food or other purposes, and a culturally sensitive ban on the sale of these animals in wet markets.” ~ Kock et al (2020).

The wild animal to human zoonotic disease pathway has received a lot of publicity recently in light of the probable origin of Covid-19 from bats infecting an unidentified animal species sold in Wuhan’s live-animal markets. Such outbreaks are likely to become more frequent if the practice of consumption of wild animals continues. Other biodiversity-related threats that increase the likelihood of pandemics include habitat loss, species extinctions, the wildlife trade, and biological invasions.

The blurring of lines between human and non-human habitat creates a spillover of wild animals and their diseases into humans. Poverty and food insecurity increase the demand for the consumption of wild animals, which shortens the odds of viral transmission through infected bodily fluids. Deforestation for timber, mining, ranching and other forms of economic activity fragment the natural world and brings humans into more frequent contact with the reservoir of pathogens that reside in animals such as monkeys, bats, and rodents. Some of these pathogens will come to infect humans. It is as if we are sitting under a tree, violently shaking that tree, letting all the creatures in the tree rain down on us, and seeing what will stick. With all that detritus raining down upon us it is inevitable that some will stick. Forest fragmentation is accompanied by road building and increased mobility, so disease transmission, which hitherto would have been localised, now has a chance to take hold in faraway densely populated settlements. This was the case with the 2014 Ebola virus outbreak which began in the tiny remote village of Meliandou in the forest region of southern Guinea and rapidly spread to teeming urban settlements in Western and Central Africa, from which it had the opportunity hitch hike a ride by plane to any location in the world. In this era of global travel what goes on in Meliandou no longer stays in Meliandou just as surely as what goes on in Wuhan no longer stays in Wuhan.  

Habitat destruction and fragmentation, climate change, selective logging and hunting, introduced species, pollution and other anthropogenic threats all contribute to species rarity and extinction. Predators such as big cats and birds of prey are often the first to go and, in their absence, the populations of their erstwhile victims can explode. Predators are nature’s quality control officers, weeding out the injured and infirm while leaving the healthy to survive and reproduce. This double whammy of growing numbers and decreased fitness among disease-transmitting animals ramps up the risk for animal to human disease transfer. Loss of other species also has human disease implications. For example, reduced numbers of amphibian species in the wake of the global spread of amphibian chytrid fungus disease may help to fuel an explosion in mosquito numbers. As people destroy more and more wild places, the web of interactions that made these ecosystems stable gradually unravels with a multitude of consequences.  

Legal and illegal trade in wildlife and wildlife products in the form of pets, trophies, crafts, food, clothing and medicines is a multi-billion dollar industry; with the profits from illicit wildlife trafficking comparable with those from the drug trade. The consequences of wildlife trade for species rarity and extinction are well known, as illustrated by ivory and rhino horn trafficking. Less publicised, is the fact that wildlife trade poses significant risks for the release of pathogens of importance to humans, domestic animals and other wildlife. A 2011 survey of found that nineteen of thirty-four (56%) of documented diseases transmitted through the movement of wildlife were linked to wildlife trade. The list includes leprosy, tuberculosis, SARS and rabies, as well as a host of animal diseases. 

Invasive species are defined as species that are not native to a specific location and have a tendency to spread to a degree to cause damage to the environment, economy or health. As a group, invasive species are responsible for the second highest number of extinctions after habitat loss. Pathogens can be considered to be invasive species with their ability to rapidly colonise much of the globe given sufficient hosts and effective modes of transmission. Invasive species that are not directly pathogenic can facilitate the spread of diseases by harbouring pathogens, disturbing habitats and making them more vulnerable to disease and creating favourable conditions for the emergence of new pathogens or re-emergence of pathogens that had been under control. In many instances, the destructive impact of an invasive species is due by the fact that species in the newly invaded ecosystem have not evolved effective defence mechanisms against the new invader – a phenomenon known as “ecological naivety”. Think of Mauritius’ flightless dodo, the poster child for extinction, that had no defence against the introduced monkeys, rats, cats and pigs which accompanied the Europeans when they first landed on the island. 

A dramatic disease-related example of ecological naivety shaping the course of history was the decimation of populations of Native Americans from smallpox (which originated in and other maladies that hitchhiked across the Atlantic in the bodies of the European conquistadors and colonisers in the 15th and 16th centuries. Smallpox was a devastating disease in Europe, but its effects were even more catastrophic on the Native Americans whose immune systems were naïve to the new pathogens, due in no small part to their lack of domesticated animals – llamas and alpacas are the only examples of successfully domesticated animals from the Americas. Smallpox (likely to have originated in camels), along with other novel pathogens such as measles (from cows and sheep), whooping cough (from pigs), typhoid (from chickens), influenza, (from domesticated ducks), and leprosy (from water buffalo) may have been responsible for wiping out 90% of all Native Americans.

​It will come as no surprise to learn that people are more susceptible to both chronic and infectious disease in polluted environments. There have been many studies on the effects of individual pollutants on health, but it is very difficult to study the impacts of a cocktail of pollutants because of the vast numbers of potential interactions between each of the cocktail’s ingredients. It is likely that each pollutant increase total body burden (fill up the stress bucket), thus increasing the likelihood of developing a chronic disease which enhances vulnerability to infections.

There are well established links between air pollution and chronic diseases, such as first-hand and second-hand smoking and atmospheric pollution inducing respiratory and cardiovascular morbidity and mortality, and extreme air pollution conditions adversely affecting blood pressure and insulin resistance.
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Domestic water sources in many parts of the world are polluted by a thousands of synthetic and natural contaminants including metals and metalloids, pesticides, industrial chemicals, pharmaceuticals, personal care products, hormones, and pathogens. The problem is most acute in the developing world but domestic water supplies in the developed world are not as pure as many people think. The figure below of risk for arsenic contamination in drinking water illustrates this reality. 

Following the discovery of intersex fish in English rivers downstream of municipal wastewater discharge in 1978, there has been growing concern about chemicals that disrupt hormonal function - endocrine disruptors. Studies suggest that these chemicals contribute to obesity and diabetes, independently of poor diet and physical inactivity. Many pollutants act as endocrine disruptors including oestrogen from the contraceptive pill, and oestrogen mimics such as bisphenol A (BPA) found in many plastics and plasticised materials such as the lining of tin cans. These compounds stimulate fat cell production and exposures across the lifespan are well documented to contribute to obesity and diabetes, which in turn enhances vulnerability to infections.

The nefarious effects of plastic pollution on our waterways, oceans and protected landscapes has been highlighted in recent years by Sir David Attenborough among others, but less well known is the part played by plastics in exacerbating the impacts of chronic and infectious diseases. Toxic compounds in plastics such as BPA and phthalates concentrate as they go up the food chain (a phenomenon known as bioaccumulation) with health impacts of the types outlined above. Like BPA, phthalates are endocrine disruptors, but they exert their effects in a different way to BPA. 
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Yet another way in which pollution contributes to disease is via the growth of mega cities in the developing world and the accompanying spread of unplanned slums with their open dumps in which nonbiodegradable plastic and rubber waste is left to accumulate. This waste provides ideal mosquito breeding grounds, notably for Aedes aegypti a vector for yellow fever, dengue fever, chikungunya and Zika virus. Aedes aegypti is known as the cockroach of mosquitoes for its ability to thrive in the human environment. 

In most circumstances, those with chronic diseases are at the greatest risk of catching infectious diseases. These diseases, which can be merely an inconvenience for the healthy, can be life-threatening for those in poor health. This statement is broadly correct, makes intuitive sense and chimes with the notion of epidemic disease as an evolutionary selective force that weeds out the vulnerable while sparing the healthy. And, the relationship between chronic and infectious diseases goes both ways, with infections in younger life often Predisposing people to chronic diseases later in life.  

But there are exceptions to the general rule, and having a specific chronic condition will not necessarily enhance somebody’s vulnerability to any one particular infectious disease. Paradoxically, the Spanish Flu of 1918-1919 appeared to be somewhat anti-Darwinian in nature and disproportionately targeted young adults.

There has been a great been a great deal of discussion about the vulnerability of certain groups to Covid-19 - essentially the elderly and those with pre-existing conditions such as chronic respiratory disease, cardiovascular disease, diabetes, cancer, and obesity and its complications. These groups are also vulnerable to seasonal influenza. However, there are exceptions. Children under five years old appear to be hardly affected by Covid-19 and those on immunosuppressive treatment for transplantation, chemotherapy or other conditions do not appear to suffer any increased risk. Despite these exceptions, countless studies make it clear that adhering to a healthy lifestyle will appreciably enhance your chances of fighting off most infectious diseases.
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Some might say that in view of the fact that the major risk factor for infectious diseases is aging and as aging is inevitable, all you are doing through a healthy lifestyle is delaying the inevitable. Indeed, the total mortality rate has been and always will be 100%. But, as previously outlined, we have lots of room to manoeuvre in terms of the number of years that we can spend in good health. There are many hallmarks of aging, such as DNA damage, exhaustion of stem cells, and systemic inflammation. Collectively these tell us our biological age which is related to but not entirely determined by our chronological age. A single marker, the “Horvath Clock” is spectacularly accurate at estimating our biological age. The test is falling in price and will soon be readily available as an objective way to measure how healthy lifestyle practices can reverse the hallmarks of aging and maintain youthful vigour into old age. 

“It's the economy, stupid” was the slogan that helped propel Bill Clinton to the White House in 1992. Clinton knew that the party or leader who is trusted the most on economic issues is the one who is likely to carry the polls. But a healthy and sustainable economy is ultimately based on a planetary life support system so at the most fundamental of levels “it’s the ecology stupid.” However, in emphasising ecological issues in this article I am not blind to the importance of the socio-economic dimensions of epidemic disease initiation, spread, and management. So, while it is critical that we get the economics right so that the economy supports the ecosystem services upon which it depends. It is also imperative that the economy functions efficiently have to enable effective management of the natural world and that the economy works for social justice. In other words a strong economy, society and planetary support system are inextricably linked. 
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The importance of these linkages is vividly illustrated in times of conflict and economic collapse, which are often accompanied by a resurgence of epidemic diseases. This has been the case in Venezuela in recent years. In 1961 Venezuela was the first country to be certified malaria-free. With the economic chaos of the past decades, thousands of destitute people have taken to the rainforest in search for gold, transforming forest into swamp, thus providing the perfect breeding grounds for malaria-transmitting Anopheles mosquitoes. Returning to urban squalor, and ravaged by disease, hapless miners have reintroduced malaria into the welcoming arms of a system rife for its resurgence – high density housing, poor sanitation, poor healthcare and no mosquito control. By 2016 malaria was back in Venezuela with a vengeance. This serves as a timely reminder that the natural and human spheres are bound together, and that individual and planetary health is a casualty if we fail to respect this reality.

The Covid-19 pandemic has functioned as a global pause button, providing us with the opportunity to reflect on how we got into this situation and on possible ways in which we can move forward once the immediate crisis has passed. As practically everybody is saying “the world will never be the same”. Business as usual cannot be an option if we are to live in harmony with the planet. But that does not mean that positive change is inevitable. If recent history is a guide, there is likely to be strong impetus to return to the status quo. Casting our minds back to the immediate aftermath of the 2008 financial crisis, there was a lot of discussion about systematic economic and financial reform, but this reform never materialised, due in no small measure to the power of vested interests. It was supposed to be a global wake-up call, but we just hit the collective snooze button.

Below, I provide a few suggestions of ways in which we can integrate measures to heal individuals and the planet upon which we all depend. The list is far from exhaustive. It is not a vainglorious attempt to replace the Sustainable Development Goals (SDGs) adopted by all United Nations Member States in 2015. Nor is it a “Marshall Plan for Planetary Health and Global Resilience”. Such a plan, if it is to fly, will take a great deal of collective reflection, discussion, negotiation and time. My humble and far from comprehensive suggestions fall into seven interconnected categories, all of which ultimately help to promote personal and planetary resilience.

• Personal health
• Climate change
• Mass animal rearing
• Biodiversity restoration
• Pollution
• Infectious diseases
• Science and public communication

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Personal health

• Shift focus from a symptom alleviation approach to a wholistic body-mind health system that focuses on root causes, behavioural change, and comprehensive and regular tests of health biomarkers for all, as a means toward the prevention, arrest and reversal of chronic disease while not ignoring acute care issues.
• Provide support for implementation of healthy behavioural change in the home, work and social environment such as classes in healthy cooking, subsidised gym membership and exercise classes, flexitime and working from home to minimise commuting time, etc.
• Provide sufficient support to existing global initiatives for infectious disease prevention, eradication, mitigation, and early detection and rapid response.

Climate change

• As a matter of urgency, prioritise all necessary steps to stay within the 1.5˚C or 2˚C warming thresholds that scientists have identified as key to the future safety of the planet. These include:
  • Increased emphasis on the role of animal consumption as a driver of climate change.
  • Removal of subsidies on activities that contribute to climate change.

Mass animal rearing

• Phase out the barbaric, unsustainable and disease-promoting practice of intensive animal agriculture by, for example, imposing minimum welfare standards, limiting the use of antibiotics and hormones, and implementing good practice for hygiene and waste management.
• Accelerate the development of healthy, low environmental footprint meat substitutes and synthetic meat products.

Biodiversity restoration

• Urgently prioritise ecosystem restoration to secure biodiversity and safeguard ecosystem function, e.g. through the development of well-funded marine parks, rewilding of areas that have lost critical ecosystem components, and development of larger and more connected protected areas with zonation in line with ecosystem function.
• Plan settlements which integrate safe and accessible contact with nature that enhances health and does not threaten biodiversity.
• Impose punitive sanctions on those benefitting from the illegal wildlife trade.
• Phase out the consumption of wild animals and invest in alternative livelihoods and sustainable development in affected communities.
• Adopt an integrated approach to biosecurity at the local, national, regional and global, levels to minimise the risks posed by invasive species that threaten  the environment, economy and health.

Pollution

• Phase out known toxins in plastics such as BPA and phthalates and develop safe, biodegradable substitutes.
• Implement measures to ensure that producers pay the full economic cost of pollution.
• Promote international good practice in domestic water treatment.
• Ensure that manufactured goods are fully recyclable.

Infectious diseases

• Adopt and go beyond a One Health approach to human animal diseases to take into account the ecology of disease formation, and spread.
• Increase investment in a safe universal influenza vaccine.
• Invest heavily in managing antibiotic resistance by optimising use in humans, minimising use in animals and developing new generation antibiotics.

Science and public communication

• Monitoring – what gets measured gets done. The scope of accurate, useful, participatory and timely monitoring of personal and planetary health parameters is immense.
• Promote high quality science that is free from compromising conflicts of interest.
• Strengthen public-funded international science and technical support networks.
• Develop a sustainably funded open access model for scientific publications to broaden dissemination of science which should be recognised as a global public good.
• Double down on fake news and false equivalence, e.g. stop giving disproportionate media coverage to climate change sceptics despite the vast preponderance of evidence.