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Further support for the benefits of regular exercise in reducing severe COVID-19 outcomes has come from a large study, the first to directly measure physical activity in its participants.
Researchers identified 65,361 members of a South African private health plan who had a COVID-19 diagnosis from March 2020 to June 2021 and matched them with physical activity data during the 2 years prior to the country’s March 2020 lockdown captured by smart devices, and clocked gym attendance and mass event participation in a voluntary healthy lifestyle behavior program linked to the insurer.
In all, 20.4% of participants had engaged in low levels of at least moderate-intensity physical activity per week (0 – 59 minutes), 34.5% in moderate levels (60 – 149 minutes), and 45.1% in high levels (150 minutes or more).
Overall, 11.1% were hospitalized as a result of COVID-19, 2.4% were admitted to the intensive care unit (ICU), 1.3% required a ventilator, and 1.6% died.
As reported in the British Journal of Sports Medicine, analyses adjusted for demographic and other risk factors showed that, with COVID-19 infection, people with high vs low physical activity had:
34% lower risk for hospitalization (risk ratio [RR], 0.66; 95% confidence interval [CI], 0.63 – 0.70)
41% lower risk for ICU admission (RR, 0.59; 95% CI, 0.52 – 0.66)
45% lower risk of requiring ventilation (RR, 0.55; 95% CI, 0.47 – 0.64)
42% lower risk for death (RR, 0.58; 95% CI, 0.50 – 0.68)
Even moderate physical exercise, below the recommended guidelines of at least 150 minutes per week, was associated with benefits:
13% lower risk for hospitalization (RR, 0.87; 95% CI, 0.82 – 0.91)
20% lower risk for ICU admission (RR, 0.80; 95% CI, 0.71 – 0.89)
27% lower risk of requiring ventilation (RR, 0.73; 95% CI, 0.62 – 0.84)
21% lower risk for death (RR, 0.79; 95% CI, 0.69 – 0.91)
“Should we come across further waves of this pandemic, our advice from a medical point of view should be to promote and facilitate exercise,” senior author Jon Patricios, MD, Wits Sport and Health, University of the Witwatersrand, Johannesburg, South Africa, said in an interview. “The likelihood is that exercise and vaccination are going to be the two most significant interventions in terms of helping to off-load the health care system rather than face the catastrophic events endured a year or so ago.”
It also suggests that the protective benefit of exercise extends to HIV-positive patients and those with rheumatoid arthritis, two groups previously not evaluated, the authors note.
The results are comparable with previous reports of self-reported exercise and COVID-19 from the United States and South Korea, although the effect of even moderate exercise was more significant, possibly due to the use of direct measures of exercise rather than self-report, Patricios suggested.
Previous data suggest that regular physical activity may protect against many viral infections including influenza, rhinovirus, and the reactivation of latent herpes viruses, he noted. However, emerging evidence also points to significant decreases in physical activity during the pandemic.
“Regular physical activity should be a message that is strongly, strongly advocated for, particularly in less well-developed countries where we don’t have access or the resources to afford pharmacological interventions in many of these scenarios,” Patricios said. “It’s frustrating that the message is not driven strongly enough. It should be part of every government’s agenda.”
The cohort all being members of a medical insurance plan could imply some selection bias based on affordability and limit generalizability of the results, the authors note. Other limitations include a lack of data on sociodemographic criteria such as education, income, and race, as well as behavioral risk factors such as smoking and diet.
Br J Sports Med. 2022;0:1-10. Full text
Patricios and coauthor Jan S. Thornton are editors of the British Journal of Sports Medicine. Several coauthors are employees of Discovery Health, Johannesburg.