Four Lifestyle Interventions to Help You Avoid Severe COVID-19

Happy Group Of Older Adults

An ounce of prevention is worth a pound of cure.” Benjamin Franklin


Setting the Scene

Unfortunately, COVID-19 has become a highly polarized topic. As a result, I have received plenty of online hate for publishing articles on social media about COVID-19.

So before we begin, I want to state for the record that this article is not about vaccination, it’s about lifestyle interventions to help you maximize your natural immune response against viruses.

Finally, I wrote this article for everyone, irrespective of whether you are pro-vaccine, anti-vaccine, or vaccine-hesitant.

The Overall Aim

The purpose of this article is to put you in the best possible position to fight off a SARS-CoV-2 infection, independently of your vaccine status.

To do this, I am hoping to achieve two broad aims.

The first aim is to help reduce your levels of chronic inflammation.

Chronic inflammation is a hallmark of many known risk factors for severe COVID-19 (1). Therefore, lowering your level of chronic inflammation may reduce the risk of triggering the hyper-inflammatory response that is so dangerous for COVID-19 patients.

The second aim is to strengthen your immune system to mount a robust and specific immune response against the SARS-CoV-2 virus should you become infected.

Intervention One: Nutrition

Salad With Berries

Recently, researchers have highlighted how poor nutrition increases your risk of suffering severe COVID-19 (2-7). Table One summarises the data from three studies that show how mortality risk changes with nutritional status (3, 5, 7).

StudyNormal Nutrition (Mortality %)Moderate Malnutrition (Mortality %)Severe Malnutrition (Mortality %)
Wei et al0%5%6.5%
Çınar et al1%4.1%25.5%
Zhao et al0%13%43.2%
Table One. Covid-19 Mortality Rates of Patients with Covid-19 Grouped By Nutritional Status (adapted from ( 3, 5, 7 )).

A Simple Approach For Optimal Nutrition

I’m a massive fan of the MIND diet (8). I’ll be writing a detailed article on the MIND diet soon. But, for now, refer to Table Two for a simple overview of the diet to get you going.

Mainly Eat These FoodsTry to Avoid These Foods
Green Leafy Vegetables: 6 or more servings a week
Other Vegetables: 1 or more servings a day
Nuts: 5 servings a week
Berries: 2 or more servings a week
Beans: 3 or more servings a week
Whole Grains: 3 servings a day
Fish (not fried): one or more meals a week
Poultry (not fried): two or more meals per week
Olive Oil: the primary source of fat in the diet
Wine: One glass per day
Red Meats
Butter and Stick Margarine
Pastries and Sweets
Fried or Fast Foods
Table Two. Basic Food Groups and Recommended Servings of the Mind Diet

Table Two. Primary Food Groups and Recommended Servings of the Mind Diet

The consumption of leafy green vegetables, other vegetables, berries, and nuts provide essential vitamins and micronutrients (9). They also offer fiber that is critical for gut health (see below).

Fish, poultry, and beans provide protein (9).

Whole grains offer a metabolically friendly source of carbohydrates. In addition, consistent with our recent article on beer, moderate wine consumption improves the function of your immune system (9).

Supplementing with Vitamins and Micronutrients

Deficiencies in essential micronutrients increase your risk of disease and death from viral infection (10).

It would be best to get all of your nutrients through eating a balanced and healthy diet. The critical point is that supplementation is only required if you are deficient in one or more micro-nutrients or vitamins.

However, there are a surprising number of people that are micro-nutrient deficient.

For example, within the US population, 45% of people are low in vitamin A, 46% for vitamin C, 95% for vitamin D, 84% for vitamin E, and 15% for zinc (9). Further, older adults are far more likely to be deficient in vitamins essential for optimal immune function.

Because vitamin deficiency increases your risk of viral infection (10), supplementation may help protect you from severe COVID-19.

Vitamin C, vitamin D, and zinc are the micronutrients with the most robust evidence for immune support (10).

Vitamin D and COVID-19

People infected with SARS-CoV-2 had lower serum vitamin D than people not infected with the virus, suggesting that adequate vitamin D protects you from SARS-CoV-2 infection (11).

Concerning COVID-19 disease outcome, there is a trend between people with low serum vitamin D and (i) increased Covid-10 disease severity, (ii) increased need for intensive care, (iii) increased requirement for forced ventilation, and (iv) increased risk of mortality (11).

Unfortunately, these results did not reach statistical significance due to the poor quality of the studies analyzed. However, the overall trend does support a role for vitamin D in protecting you from severe COVID-19.
Two of the three clinical trials analyzed showed that vitamin D supplementation reduced disease severity, with no effect on the third trial (11).

Collectively, the combined data support vitamin D supplementation as a way for you to avoid infection and also reduce the severity of COVID-19 if you become infected (11).

Zinc and COVID-19

You need to maintain adequate levels of zinc for your immune system to work effectively.

For this reason, zinc deficiency makes people more vulnerable to intestinal and respiratory infections. Unfortunately, the elderly, vegans and vegetarians, and individuals with chronic diseases are often deficient in zinc.

Multiple clinical trials have shown that zinc supplementation shortens the duration of the common cold (12). In addition, there are good reasons to believe that zinc supplementation also protects you from severe COVID-19 (13, 14). Indeed, the only clinical trial performed to date showed that zinc supplementation improved COVID-19 outcomes (15).

Thus, the collective data support the hypothesis that zinc supplementation is protective against severe COVID-19.

Vitamin C and COVID-19

Vitamin C is interesting. Although most people believe that vitamin C protects you against respiratory viral infections, this is generally not the case. Analysis of 24 clinical trials showed that vitamin C supplementation at 200 mg/day did not reduce the common cold incidence (16). However, although the effects weren’t dramatic, vitamin C supplementation did tend to shorten the duration and severity of colds (16).

It’s a different story in athletes. For example, in marathon runners, skiers, and soldiers on sub-arctic exercises, vitamin C supplementation reduced the incidence of colds by a whopping 52% (16)!

Thus, even if you are sedentary, vitamin C supplementation likely has some benefit in protecting you from COVID-19. Crucially, vitamin C supplementation may provide significant protection against COVID-19 and other viruses if you are training hard or competing at a high level in sport.

Take-Home Message Number One

You can reduce the chance of succumbing to severe COVID-19 by improving your nutrition and ensuring that you are not deficient in essential vitamins and minerals, particularly zinc, vitamin C, and vitamin D.

Intervention Two: Gut Health

Woman Healthy Gut Image

What is a healthy gut?

Your gut is a complex ecosystem consisting of millions of bacteria, collectively known as your gut microbiome. Don’t freak out, but your gut microbiome can weigh up to 2 kg!

A healthy gut microbiome plays a critical role in maintaining your health (17). Briefly, a healthy gut microbiome provides the following beneficial functions (17):

  • Improved metabolic health
  • Produce critical bacterial metabolites, such as short-chain fatty acids (SCFAs), helping to support your immune system
  • Preserves the structural integrity of the gut mucosal barrier
  • Protects you against pathogens

In contrast, having an unhealthy gut microbiota is a state called dysbiosis. People with dysbiosis have a less diverse and less stable bacterial population that often includes pathogenic bacteria (17).

Dysbiosis has many adverse consequences, such as poor metabolic health and a compromised gut mucosal barrier. In addition, the reduced gut barrier integrity caused by dysbiosis allows bacteria and toxins to enter your bloodstream, triggering an inflammatory response that may exacerbate the risk of severe COVID-19 (18).

The Gut-Lung Axis

There is increasing evidence that your gut microbiome affects your lung health (19). For example, gut dysbiosis contributes to asthma, tuberculosis, and lung cancer (19). However, how the lungs and gut communicate is still not fully understood.

Nevertheless, a distributed ‘mucosal immune response’ exists where the gut microbiome influences your immune response at distal mucosal sites, such as the lung. Notably, several studies indicate that dysbiosis can increase the severity of respiratory virus infections, such as influenza (20).

Thus, maintaining your gut health may protect you against the effects of respiratory viruses.

The link between Dysbiosis and Severe COVID-19

Several risk factors for severe COVID-19, such as age, diabetes, and hypertension, are associated with gut dysbiosis (21). In addition, SARS-CoV-2 infected patients who developed COVID-19 disease have significantly different gut microbiomes compared with asymptomatic SARS-CoV-2 patients (18).

Furthermore, new evidence suggests that suffering a SARS-CoV-2 gut infection can lead to dysbiosis (22). Moreover, the dysbiosis caused by COVID-19 disease may persist long after the SARS-CoV-2 infection has cleared, as shown in a recent study that demonstrated dysbiosis persisting in COVID-19 survivors 3 months after their infection had cleared (23).

Thus dysbiosis may be a risk factor for COVID-19 and long COVID.

Why Gut Health is Important for Avoiding COVID-19

To summarize the story so far, actively maintaining your gut health may be protective against COVID-19 for the following reasons.

  1. A healthy gut reduces inflammation, which could help you avoid a severe inflammatory response to a SARS-CoV-2 infection.
  2. Gut dysbiosis makes other respiratory virus infections, such as influenza, more severe. Therefore, gut dysbiosis may increase the risk of severe COVID-19 after SARS-CoV-2 infection.
  3. Associations between gut microbiota composition and inflammatory markers in patients with COVID-19 suggest that an unhealthy gut microbiome increases the risk of COVID-19 (18).
  4. COVID-19 can cause dysbiosis, which can last several months after SARS-CoV-2 infection (18, 23).

Therefore, COVID-19-induced dysbiosis may increase the risk of long-COVID (18, 23).

Thus, although researchers have not yet formally established the link between gut health and COVID-19 in randomized clinical trials, there are good reasons for you to believe that maintaining a healthy gut helps protect you against COVID-19.

Four Ways to Maximise Your Gut Health

Fortunately, there are safe and effective ways for you to improve and maintain your gut health.

1. Fiber

The best and most important intervention to improve and maintain your gut health is following a healthy diet (24, 25). In a nutshell, maintaining a nutrient-rich diet with plenty of fiber maintains a diverse gut microbiome that helps keep you healthy (25).

We recommend two diet options: the MIND diet and the Mediterranean diet, which provide a large proportion of mixed vegetables and unsaturated fats to support a healthy gut microbiome.

However, any diet low in saturated fat and high in plant material, particularly fiber, supports a healthy gut microbiome (25).

2. Prebiotics

Prebiotics are nutrients that preferentially support the growth and proliferation of beneficial bacteria in your gut (26). Prebiotics are present in leek, asparagus, chicory, Jerusalem artichoke, garlic, artichoke, onion, and banana (26).

Of course, you can readily supplement your diet with prebiotics or consume prebiotic-fortified foods and supplements to help maintain a healthy gut biome (26).

3. Probiotics

A probiotic is a ‘live micro-organisms that, when administered in adequate amounts, confer a health benefit on the host’ (27). Some established positive effects of probiotic consumption are protection against gastroenteritis, improved lactose tolerance, stimulation of the immune system, and reductions in blood lipids (26).

In humans, the most common forms of probiotics are fermented milk products (e.g., yogurt) and freeze-dried preparations of beneficial bacteria in capsules (26).

4. Exercise

Multiple, carefully controlled animal studies have shown that aerobic exercise changes the gut microbiome and increases the production of bacterial metabolites that increase the gut barrier’s integrity and support healthy immune function (28). In addition, studies in humans support the idea that regular exercise supports a healthy gut microbiome.

However, there are several caveats to using exercise for improving your gut health.

First, the effects of exercise on your gut microbiome disappear if you stop exercising (28). Second, exercise has the most beneficial effects for improving gut microbiome health in lean individuals (28). Finally, although a short duration of light-to-moderate aerobic training may improve your gut microbiome, a longer duration at a higher intensity may be required to induce significant improvements in your gut microbiome composition (28).

Thus, lean individuals who train hard for extended periods experience the most significant improvements to their gut health (28).

Take-Home Message Two

Interventions such as following a healthy diet, prebiotic and probiotic supplementation, and aerobic exercise are safe and effective options for improving your gut health and reducing the risk of severe COVID-19.

Intervention Three: Exercise

Woman Running

Exercise reduces your risk of acquiring a respiratory viral infection in the community (29) and dying from a respiratory virus if you become infected (29).

But what about SARS-CoV-2, the virus responsible for the COVID-19 pandemic?

A recent article published in the British Journal of Sports Medicine looked at how physical activity protected 48 440 adult patients diagnosed with COVID-19 (30).

Specifically, they linked physical activity (classified as inactive = 0 – 10 min/week, some activity=11 – 149 min/week, consistently meeting guidelines = 150 + min/week) to the risk of (i) hospitalization, (ii) intensive care admission and (iii) death after COVID-19 diagnosis (30).
The results of their analysis are striking.

Patients with COVID-19 who were consistently inactive had (i) a 2.26 elevated risk of hospitalization, (ii) a 1.73 increase in the risk of admission to intensive care, and (iii) a 2.49 increase in the risk of death due to COVID-19 compared to COVID-19 diagnosed patients who consistently met physical activity guidelines (30).

To quote the Authors directly:

The magnitude of risk for all outcomes associated with being consistently inactive exceeded the odds of smoking and virtually all the chronic diseases studied in this analysis, indicating physical inactivity may play a crucial role as a risk factor for severe COVID-19 outcomes’ (30).

The authors conclude that ‘Pandemic control recommendations should include regular physical activity across all population groups’ (30).

The Long-Term Protective Effects of Exercise Against COVID-19

A second study has revealed the remarkable long-term protective effect of physical fitness. Here, the Author’s assessed how physical fitness at a young age protects you against disease many years later.

First, the Authors retrieved over one million Swedish men’s cardio-respiratory fitness (CRF) levels while serving in the military between 1968 and 2005. Then, they assessed how the historic CRF values affected the risk of hospitalization, intensive care, or dying due to COVID-19 in 2020 (31).

Strikingly, high cardiorespiratory fitness at a young age reduces the risk of COVID-19 hospitalization by 24%, intensive care by 39%, and death by 44% (31). In addition, the protective effect of physical fitness against severe COVID-19 occurred in people of all ages, weights, and despite the presence of chronic disease (31).

Thus, cardiorespiratory fitness at a young age protects people later in life against severe COVID-19.

How to Exercise for Maximal COVID-19 Protection

The most protection against COVID-19 occurs in people who have performed at least 150 minutes per week of moderate exercise targeting the cardiorespiratory system (30, 31).

Although strength training offers some protection against COVID-19, aerobic fitness appears far more effective (30, 31). Thus, we recommend that improving your aerobic fitness should become a priority in your training program.

However, training sessions that last longer than one hour become stressful on your body, which can suppress your immune system (32). For this reason, you should train as efficiently as possible to get your workout done in under an hour. A straightforward approach is to perform four 40-minute sessions of cardio four days a week.

Currently, there are no clear recommendations on which type of training is optimal. However, steady-state cardio, high-intensity interval training (HIIT), or sprint interval training (SIT) improve cardiorespiratory fitness. So, pick the type of training you enjoy most.

Unfortunately, it takes time to improve your fitness levels for virus protection. For example, it took 20 weeks of regular exercise to observe an improvement in the immune response in patients (29). Thus, although exercise helps protect you against viral disease, it’s not a quick fix.

Take-Home Message Three

Cardiorespiratory fitness appears to provide long-term protection against COVID-19 despite the presence of other risk factors, such as obesity and chronic disease (31).

For these reasons, you should perform 3-5 workouts consisting of moderate physical activity each week, keeping each session to under one hour.

Intervention Four: Sleep

Woman And Cute Dog Sleeping

The importance of sleep for your immune response is evident when we consider the effect of sleep deprivation on vaccine response.

For example, reducing your sleep four days before an influenza vaccination can reduce your antibody production from the flu vaccine by over 50% (reviewed in (33)).

Furthermore, suppose you don’t sleep the night after receiving a hepatitis-A, hepatitis-B, or influenza vaccine. In that case, you also reduce your antibody response to the vaccine by about 50% (reviewed in (33)).

Thus, being sleep deprived either before or immediately after receiving your vaccine reduces the vaccine’s protective effect.

Sleep and COVID-19 Vaccine Response

Does sleep quality impact your immune response to the SARS-CoV-2 vaccine?

Unfortunately, we currently don’t have a definitive answer to this question (34). However, given how sleep deprivation negatively impacts the efficacy of other vaccines, it is likely that disrupted sleep reduces the effectiveness of the COVID-19 vaccine (34).

Maximizing your immune response to the COVID-19 is very important for three reasons.

First, for those of you who have a compromised immune system (for example, people over the age of 70), ensuring you are sleeping well before and after your vaccine may be necessary to provide a protective immune response post-vaccination (34).

Second, the emergence of Sars-CoV-2 variants that can now partially avoid the vaccine immune response means that everyone should maximize their immune response to the COVID-19 vaccine.

Finally, some researchers have found that antibody responses rapidly wane after COVID-19 vaccination (35).
Now, before you panic, it’s normal for antibody levels to decline after any virus infection. Remember, it’s the memory cells of your immune system that provide long-lasting protection, not your short-lived antibody response. Nevertheless, a more robust antibody response after your vaccine produces more memory immune cells, which reduces your chance of infection (35).

Thus, the current recommendation is that you should focus on getting as much quality sleep as possible before and after your COVID-19 vaccination (35, 36).
Sleep and Virus Infection

It should come as no surprise that sleep is also crucial for protecting you from infection.

For example, people who report poor sleep are more likely to suffer from respiratory diseases and succumb to pneumonia than those who experience adequate sleep (reviewed in (33)).

In addition, those who experience disrupted sleep report experiencing more frequent cold, influenza, and gastro infections than those who sleep well (reviewed in (33)).

Finally, virus challenge experiments show that people who experienced impaired sleep had an increased chance of developing a cold after receiving cold virus nasal drops (reviewed in (33)).

Thus, disrupted sleep makes you vulnerable to virus infections.

Sleep and COVID-19 Disease

Unfortunately, the role between sleep and COVID-19 remains understudied. Currently, the only known link between sleep and COVID-19 is the link between sleep apnea and severe COVID-19.

Obstructive sleep apnea (OSA) is a sleep breathing disorder caused by obstructions of the upper airway during sleep (37). Recently, researchers identified OSA as a risk factor for severe COVID-19 (38).

Given that chronic sleep disruption increases inflammation and reduces anti-viral immunity (35), it makes sense that the presence of OSA can tip patients towards the state of runaway inflammation that increases the severity of COVID-19 (33).

Thus, it’s likely that sleep disruption increases your risk of suffering severe COVID-19.


Melatonin is produced in the brain during periods of darkness and is an essential regulator of your sleep-wake cycle (a.k.a, your circadian rhythm) (39).

The sleep-related roles of melatonin are promoting sleep, maintaining sleep, resetting your circadian clock, and training your circadian rhythm over time (39). Unfortunately, your natural melatonin production declines as you age, which contributes to age-related insomnia.

In addition, melatonin has several non-sleep-related roles in maintaining your health. For example, melatonin is an antioxidant, has anti-inflammatory effects, and is neuro- and cardio-protective (39-41).

When taken as a drug, melatonin appears to be a safe and effective sleep aid (42). Furthermore, the additional biological effects of melatonin mean that it may offer additional protection against COVID-19 (43).

Before you rush to the chemist to stock up on melatonin, please check with your doctor. Because various melatonin formulations are available, matching the correct melatonin formulation to your specific sleep disruption produces optimal sleep results (43).

Only your doctor can identify which melatonin formulation is suitable for you.

Take-Home Message Four

High-quality sleep is vital to protect you against virus infection. In contrast, disrupted sleep increases chronic inflammation, makes you vulnerable to viral infection, and dampens your vaccine immune response. For these reasons, getting consistent, high-quality sleep is an essential part of your COVID-19 defenses.


By focusing on optimizing your diet, keeping your gut healthy, building a cardiovascular fitness base, and getting consistent, high-quality sleep, you are tipping the odds in your favor for avoiding severe COVID-19.

In addition, this approach also protects you from other respiratory viruses, such as influenza.

Lifestyle Interventions Protect Covid 19

References and Further Reading

  1. A. Vepa, J. P. Bae, F. Ahmed, M. Pareek, K. Khunti, COVID-19 and ethnicity: A novel pathophysiological role for inflammation. Diabetes Metab Syndr 14, 1043-1051 (2020).
  2. L. Curtis, Good nutrition critical to prevent Covid 19 mortality. Heart Lung 50, 441 (2021).
  3. T. Çınar et al., Is prognostic nutritional index a predictive marker for estimating all-cause in-hospital mortality in COVID-19 patients with cardiovascular risk factors? Heart Lung 50, 307-312 (2021).
  4. D. Bedock et al., Prevalence and severity of malnutrition in hospitalized COVID-19 patients. Clin Nutr ESPEN 40, 214-219 (2020).
  5. C. Wei et al., Evaluation of the nutritional status in patients with COVID-19. J Clin Biochem Nutr 67, 116-121 (2020).
  6. R. Wang et al., The Prognostic Nutritional Index is associated with mortality of COVID-19 patients in Wuhan, China. J Clin Lab Anal 34, e23566 (2020).
  7. X. Zhao et al., Evaluation of Nutrition Risk and Its Association With Mortality Risk in Severely and Critically Ill COVID-19 Patients. JPEN J Parenter Enteral Nutr 45, 32-42 (2021).
  8. M. C. Morris et al., MIND diet slows cognitive decline with aging. Alzheimers Dement 11, 1015-1022 (2015).
  9. S. Cohen, Psychosocial Vulnerabilities to Upper Respiratory Infectious Illness: Implications for Susceptibility to Coronavirus Disease 2019 (COVID-19). Perspect Psychol Sci 16, 161-174 (2021).
  10. A. F. Gombart, A. Pierre, S. Maggini, A Review of Micronutrients and the Immune System-Working in Harmony to Reduce the Risk of Infection. Nutrients 12, (2020).
  11. A. Bassatne et al., The link between COVID-19 and VItamin D (VIVID): A systematic review and meta-analysis. Metabolism 119, 154753 (2021).
  12. H. Hemilä, Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open 8, 2054270417694291 (2017).
  13. D. N. Marreiro et al., Anti-viral and Immunological Activity of Zinc and Possible Role in COVID-19. Br J Nutr, 1-21 (2021).
  14. E. Finzi, Treatment of SARS-CoV-2 with high dose oral zinc salts: A report on four patients. Int J Infect Dis 99, 307-309 (2020).
  15. P. M. Carlucci et al., Zinc sulfate in combination with a zinc ionophore may improve outcomes in hospitalized COVID-19 patients. J Med Microbiol 69, 1228-1234 (2020).
  16. H. Hemilä, E. Chalker, Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev 2013, Cd000980 (2013).
  17. K. A. Lee et al., The gut microbiome: what the oncologist ought to know. Br J Cancer, (2021).
  18. Y. K. Yeoh et al., Gut microbiota composition reflects disease severity and dysfunctional immune responses in patients with COVID-19. Gut 70, 698-706 (2021).
  19. K. F. Budden et al., Emerging pathogenic links between microbiota and the gut-lung axis. Nat Rev Microbiol 15, 55-63 (2017).
  20. V. L. Ngo, A. T. Gewirtz, Microbiota as a potentially-modifiable factor influencing COVID-19. Curr Opin Virol 49, 21-26 (2021).
  21. N. S. Magalhães, W. Savino, P. M. R. Silva, M. A. Martins, V. F. Carvalho, Gut Microbiota Dysbiosis Is a Crucial Player for the Poor Outcomes for COVID-19 in Elderly, Diabetic and Hypertensive Patients. Front Med (Lausanne) 8, 644751 (2021).
  22. G. L. V. de Oliveira, C. N. S. Oliveira, C. F. Pinzan, L. V. V. de Salis, C. R. B. Cardoso, Microbiota Modulation of the Gut-Lung Axis in COVID-19. Front Immunol 12, 635471 (2021).
  23. Y. Tian et al., Gut Microbiota May Not Be Fully Restored in Recovered COVID-19 Patients After 3-Month Recovery. Front Nutr 8, 638825 (2021).
  24. I. Rowland et al., Gut microbiota functions: metabolism of nutrients and other food components. Eur J Nutr 57, 1-24 (2018).
  25. S. Anand, S. S. Mande, Diet, Microbiota and Gut-Lung Connection. Front Microbiol 9, 2147 (2018).
  26. G. E. Walton, G. R. Gibson, K. A. Hunter, Mechanisms linking the human gut microbiome to prophylactic and treatment strategies for COVID-19. Br J Nutr 126, 219-227 (2021).
  27. C. Hill et al., Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 11, 506-514 (2014).
  28. L. J. Mailing, J. M. Allen, T. W. Buford, C. J. Fields, J. A. Woods, Exercise and the Gut Microbiome: A Review of the Evidence, Potential Mechanisms, and Implications for Human Health. Exerc Sport Sci Rev 47, 75-85 (2019).
  29. S. F. M. Chastin et al., Effects of Regular Physical Activity on the Immune System, Vaccination and Risk of Community-Acquired Infectious Disease in the General Population: Systematic Review and Meta-Analysis. Sports Med 51, 1673-1686 (2021).
  30. R. Sallis et al., Physical inactivity is associated with a higher risk for severe COVID-19 outcomes: a study in 48 440 adult patients. Br J Sports Med, (2021).
  31. A. Af Geijerstam et al., Fitness, strength and severity of COVID-19: a prospective register study of 1 559 187 Swedish conscripts. BMJ Open 11, e051316 (2021).
  32. D. C. Nieman, L. M. Wentz, The compelling link between physical activity and the body’s defense system. J Sport Health Sci 8, 201-217 (2019).
  33. L. Besedovsky, T. Lange, M. Haack, The Sleep-Immune Crosstalk in Health and Disease. Physiol Rev 99, 1325-1380 (2019).
  34. C. Benedict, J. Cedernaes, Could a good night’s sleep improve COVID-19 vaccine efficacy? Lancet Respir Med 9, 447-448 (2021).
  35. A. Hamady, J. Lee, Z. A. Loboda, Waning antibody responses in COVID-19: what can we learn from the analysis of other coronaviruses? Infection, 1-15 (2021).
  36. C. S. Kow, S. S. Hasan, Do sleep quality and sleep duration before or after COVID-19 vaccination affect antibody response? Chronobiol Int 38, 941-943 (2021).
  37. M. T. Mello et al., Sleep and COVID-19: considerations about immunity, pathophysiology, and treatment. Sleep Sci 13, 199-209 (2020).
  38. B. E. Cade, H. S. Dashti, S. M. Hassan, S. Redline, E. W. Karlson, Sleep Apnea and COVID-19 Mortality and Hospitalization. Am J Respir Crit Care Med 202, 1462-1464 (2020).
  39. L. M. Melhuish Beaupre, G. M. Brown, V. F. Gonçalves, J. L. Kennedy, Melatonin’s neuroprotective role in mitochondria and its potential as a biomarker in aging, cognition and psychiatric disorders. Transl Psychiatry 11, 339 (2021).
  40. M. Ashrafizadeh et al., Anti-Inflammatory Activity of Melatonin: a Focus on the Role of NLRP3 Inflammasome. Inflammation 44, 1207-1222 (2021).
  41. A. Wichniak, A. Kania, M. Siemiński, W. J. Cubała, Melatonin as a Potential Adjuvant Treatment for COVID-19 beyond Sleep Disorders. Int J Mol Sci 22, (2021).
  42. G. Fatemeh et al., The effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials. J Neurol, (2021).
  43. I. Moroni et al., Pharmacokinetics of exogenous melatonin in relation to formulation, and effects on sleep: A systematic review. Sleep Med Rev 57, 101431 (2021).


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Powerful Older Man

F*ck Frailty!

Frailty is preventable, and often reversible, if you are willing to put in the work and follow the three golden rules of resistance training.

Woman Yoga Nidra for sleep

Yoga Nidra for Better Sleep

Disrupted sleep increases anxiety and depression. Yoga Nidra is an effective method that has helped many people overcome insomnia.

Beautiful Woman Running On Treadmill

Low-Intensity Cardio for Metabolic Health

Emerging research shows that low-intensity cardio is the best way to improve your metabolic and cardiovascular health.