During the COVID-19 virus pandemic, researchers have found a number of risk factors for increased COVID severity. These risk factors include age and race, along with preexisting diabetes, obesity, hypertension, kidney disease, and respiratory illnesses. It is well established that the majority of COVID-related hospitalizations and deaths have occurred among individuals with these risk factors, with even greater risk among those who were also unvaccinated. Because the benefits of regular physical activity (PA) include a protective effect against the severity of respiratory infections, several studies have examined the relationship between PA and COVID severity, i.e., hospitalization and death.
In previous blogs, we have discussed the technique of meta-analysis. Briefly, a meta-analysis combines individual similar studies into one large study. Recently, a group of Spanish researchers performed a meta-analysis on PA and COVID severity. Sixteen published studies with nearly 2 million participants were combined. Physical activity level was assessed via questionnaire in most of the studies, although three studies utilized accelerometers or smart devices. PA was then classified based on the total number of MET-minutes per week. The average age of the participants was 53 years, men and women were represented nearly equally, and the studies included in the meta-analysis came from over a dozen different countries. During the follow-up, there were a total of 134,639 positive cases of COVID, with 20,984 hospitalizations for COVID, 7,009 cases of severe COVID (i.e., intensive care unit and/or ventilation use), and 2,878 COVID-related deaths.
A summary of the results is as follows:
When compared to those not meeting current guidelines for PA, those meeting PA guidelines (at least 500 MET-minutes each week*) were
- 11% less likely to become infected with COVID
- 36% less likely to be hospitalized for COVID
- 34% less likely to experience severe COVID
- 43% less likely to experience COVID-related death
These data add to a substantial body of literature showing that regular PA has beneficial effects on the immune system. The authors of the current study emphasized that physicians and healthcare policymakers should make appropriate PA recommendations at the individual and population level. Doing so would very likely help reduce the likelihood of adverse COVID outcomes, particularly in high-risk patients.
*500 MET-minutes each week is equivalent to 150 minutes of moderate intensity or 75 minutes of vigorous intensity physical activity per week.
Ezzatvar, Y., et al. (2022). Physical activity and risk of infection, severity, and mortality of COVID-19: A systematic review. British Journal of Sports Medicine. Published ahead of print. doi: 10. 1136/bjsports-2022-105733