Physical Inactivity & the COVID-19 Pandemic

The Health Benefits of Exercise Report is a newsletter and article series in which we select three peer-reviewed articles, summarize the key findings, and provide social media images for you to share with your community. You can read previous articles here.

As the COVID-19 pandemic persists, maintaining a physically active lifestyle continues to present a challenge. However, we know that exercise is a key measure to help prevent chronic health conditions that still affect millions of people and increase the risk of severe COVID-19. This month’s edition of Health Benefits of Exercise Report covers:

1. Evidence regarding the impact of physical activity on several aspects of COVID-19
2. A review of the evidence on a number of factors—including physical activity—associated with Alzheimer’s disease risk
3. A study looking at the efficacy of adding physical activity interventions to behavioral therapy for depression and anxiety

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. An 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.

Physical Activity May Play a Role in Helping to Prevent Alzheimer’s

Approximately 50 million people around the world live with Alzheimer’s disease, a type of dementia. Some reports have suggested that the incidence and prevalence of dementia have declined in recent years, but evidence of effective prevention measures is largely inconsistent. A study published in the Journal of Neurology, Neurosurgery, & Psychiatry conducted a systematic review of randomized controlled trials and long-term observational studies. The authors reviewed a total of 396 studies.

The authors conducted meta-analyses on 134 risk factors, including:

• diabetes,
• history of smoking,
• body mass index,
• physical activity,
• serum folate,
• pesticide exposure, and
• blood pressure, among others.

The analysis found 43 factors that showed a statistically significant association with Alzheimer’s disease risk, 80% of which modified risk by at least 25%. Physical activity was one such factor; the analysis found a reduced risk of 36%.

Additionally, some of the factors associated with a higher risk of Alzheimer’s can be prevented or mitigated to varying extents by a physically active lifestyle. These factors include:

• having diabetes,
• obesity in mid-life,
• hypertension in mid-life,
• stroke, and
• high cholesterol.
  

Exercise May Be an Effective Addition to Behavioral Therapy for Depression

A study published in the journal Behavioral Sciences looked at the effect of exercise interventions combined with behavioral therapy to treat anxiety and depression. The analysis included participants with/without comorbidities—such as HIV or heart disease—and with/without elevated depression levels. The behavioral therapies included cognitive behavioral therapy, psychotherapy, and stress management, among others, and exercise interventions included aerobic exercise only (nine studies), resistance exercise (two studies), and combined aerobic and resistance exercise (six studies). In total, the systematic review and meta-analysis included 18 studies involving 1,686 participants.

According to the results, combined behavioral therapy and exercise intervention showed a statistically significant benefit compared to behavioral therapy alone for people with depression. Specifically, moderate exercise intensity and aerobic only interventions combined with behavioral therapy were associated with improvements in depression. The effect was more pronounced in older participants. There was no difference between groups for people with anxiety.

Depression often occurs alongside other chronic health conditions, many for which exercise is linked to physical and mental health benefits. The authors conclude that adding exercise interventions to existing behavioral therapy for people with depression may be an inexpensive but effective way to enhance treatment benefits.

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