“Health is an Investment, not An Expense”

Welcome back to Pete’s Blog. The blog has been in hibernation for the last six months, initially as a consequence of the government shutdown and then while our focus was directed to reopening the gym.

This month I am exploring the benefits of regular exercise and a healthy diet for developing and maintaining a healthy immune system throughout our lifecycle.

First up I report on a recent scientific study where the authors investigated the health benefits of regular physical activity on the Immune System, Respiratory Tract, Cardiovascular System and also Mental Health. Secondly I look at the importance of regular physical activity on maintaining a healthy immune system as we age and then finally the link between a healthy diet and a strong immune system.

The Relationship Between Physical Inactivity & COVID-19

Given the novelty of the SARS-COV2 virus, which causes COVID-19, it is not surprising that there have not been many studies on the relationship between physical activity and COVID-19 outcomes. A recent article published in Sports Medicine and Health Science reviews the available evidence regarding the impact of COVID-19 on several physiological systems and any potential relationship with physical activity.

Immune System: Moderate physical activity may reduce susceptibility to upper respiratory tract infections, and physical activity can benefit immune system health. The authors note that, while more studies are needed to assess the link between physical activity prior to COVID-19 diagnosis and COVID-19 outcomes, exercise during the pandemic is recommended and can also help mitigate some comorbidities such as diabetes and obesity.

Respiratory Tract: In severe COVID-19 cases requiring hospitalization, 54% of patients experience respiratory failure, and more than 30% require mechanical ventilation. People on mechanical ventilation for long periods can develop a weakened diaphragm, making it harder to wean them off the ventilator. Physical activity is not known to change the structure and function of the lung and airways; however, endurance training may promote biochemical adaptations that help protect against challenges, including prolonged ventilation. In one study, as few as 10 consecutive days of aerobic exercise training provided statistically significant protection against diaphragm weakening. In theory, this would mean trained individuals who require mechanical ventilation would have some protection against a weakened diaphragm and thus experience fewer challenges coming off the ventilator.

Cardiovascular System: With COVID-19, exercise can have both positive and negative effects. When recovering from COVID-19, some people experience cardiac damage (such as myocarditis or inflammation in the heart muscle, which has afflicted several collegiate and professional athletes). This cardiac damage can increase the risk of sudden cardiac death during exercise and may extend throughout the lifetime.

On the positive side, physical activity promotes heart health and longevity. The authors recommend healthy people during and after the pandemic to “remain physically active and exercise while socially distanced when you are well, stop exercise when you develop symptoms or signs of an infection, and return to PA and exercise slowly following recovery.”

Mental Health: The authors also discuss the detrimental effects of quarantine-related depression and conclude that “regular exercise can attenuate the symptoms and consequences of quarantine-induced depression and traumatic disorders with the systemic, complex, and powerful neuroprotective effects.

Overall, the authors recommend exercise sessions of moderate-intensity and up to 45 minutes in length for immune health and advise older adults to get at least 30 minutes of moderate exercise two to three times per week.

Source: Woods JA, Hutchinson NT, Powers SK, et al. The COVID-19 pandemic and physical activity. Sports Medicine and Health Science. 2020;2(2):55-64.

Physical Activity Can Help Support Healthy Immune System Aging

As part of the aging process, the immune system undergoes a process called immunosenescence, a decline in some immune cell functions. Immunosenescence is characterized by increased susceptibility to infection, decreased vaccine efficacy, and higher prevalence of autoimmunity and cancer. A review published in the journal “Nutrients”discussed available evidence on immune system protection through physical activity.

The review found evidence from cross-sectional and intervention studies comparing lower fitness to higher fitness older adults suggesting a beneficial effect of exercise on certain immune cells. The review also suggests that exercise may reverse age-related changes or reduce the decline of some immune cells. The authors also note the widely accepted view that physical activity has an anti-inflammatory effect, outlining several mechanisms by which activity affects inflammation.

There is also evidence that exercise is beneficial for vaccine efficacy. In two studies included in the review, older adults who were active regularly saw increased antibody responses to the influenza vaccine compared to inactive peers of the same age. The authors conclude that “exercise is an effective strategy for supporting successful immune aging and decreasing the risk of maladaptive immune aging. In this regard, regular endurance exercise seems to be the most promising approach to counteracting cellular immunosenescence and inflammaging.”

Source: Weyh C, Krüger K, Strasser B. Physical Activity and Diet Shape the Immune System during Aging. Nutrients. 2020;12(3):622. Published 2020 Feb 28.

Supporting your immune function with a healthy diet

Finally, the important role that good nutrition plays in having a strong immune system and in turn helping us to reduce the risk of illness.

Prioritise quality nutrition

Eat a variety of foods across all food groups to provide a wide range of nutrients. Specifically, eating a variety of brightly coloured fruits and vegetables will provide plenty of micronutrients (like vitamins and antioxidants) that are known to be beneficial for immune function.

Aim for at least 2 serves of fruit and 5 serves of vegetables every day. In addition, eating red meat and their alternatives will provide the minerals iron and zinc, which are also important for good immune function.

Fuel appropriately

Under-fuelling (i.e. not eating enough) can compromise our immune function. Therefore, it is essential to consume enough energy to meet the demands of training loads. Specifically, make sure you are fuelling your training with carbohydrate-based snacks and top up during long sessions. On days with a higher training volume and intensity, you will need to consume more carbohydrate.

DO

✓ Consider the use of probiotics...foods such as yoghurt, kefir and fermented foods like sauerkraut;

or a supplement (your GP or Sports Dietitian can guide you on this).

✓ Head outside and get some fresh air and a little sunshine for Vitamin D.

✓ Get adequate and good quality sleep.

✓ Reach out as needed for management of stress.

✓ Wash your hands, especially prior to eating.

DON’T

× Don’t - consume excessive alcohol.

× Don’t - over-train. Ensure training loads are managed well.

× Don’t - bother with a multi-vitamin. A balanced diet should provide all the vitamins and minerals you need.

Putting this into practice

• Plan out your weekly meals, considering your exercise schedule where possible. Aim to vary your meals to ensure a wide range of nutrients.

• When making your shopping list, make sure to include appropriate snacks so that you can meet your recovery requirements.

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Pete’s Blog – September 2020