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Fitness and Lower Likelihood of COVID-​19 Death Link Found

May 10/2021

by Françoise Makanda, Communications Officer at DLSPH

U of T researchers have found that fit people are less likely to die from COVID-19.

“One of the really cool findings of this study is that anyone with an above low level of physical activity is better protected,” says Rebecca Christensen, a DLSPH PhD student and lead author of the study, published last week in PLOS One. “Running once in a blue moon won’t protect you but if you are running regularly, you’re doing fine.”

Photo of Rebecca Christensen

PhD student Rebecca Christensen

While there is no prescription on what ‘good fitness’ means, researchers observed that even low-to-moderate exercise seems to make a difference.

“Someone who just goes from doing no fitness to doing some fitness, could see appreciable benefits. And that’s why we pulled data based on age and activity-level thresholds. We want to see if you could just do something, will it have an impact? The answer is yes — as long as you’re doing something consistently.”

Using the UK Biobank, researchers focused solely on the risk associated with death and the likelihood of catching the virus, not disease severity which would include hospitalization. The data range was limited to ages 49 to 80, but the sample was large enough to look at COVID-specific death.

The team assessed the dataset and observed physical activity by percentile within ten-year age bands given the UK Biobank’s limited variables. The lowest 20th percentile was categorized as low fitness; the 40th to 80th percentile was moderate; and above the 80th percentile was above average . Physical activity declines with age but “if you’re fitter for people within your age group, are you going to have a benefit? The answer is still yes,” she says.

A routine must include a cardio intense workout, one where you break a sweat or are breathing heavily says Christensen, but you don’t need to be a marathon runner. The greatest benefit is in moving from inactivity to some consistent amount of physical activity.

And, while there are known cases of athletes catching COVID-19, Christensen argues that the nature of their work increases the likelihood of catching COVID-19. Most are exercising in an environment with others in close settings. And symptoms severity could be linked to the physical stress of the athlete’s intense workouts.

“People who exercise a lot can actually have a decrease in their immune system by over exercising,” she notes.

The World Health Organization has recently doubled its recommended physical activity guideline. “We’ve got up to 300 minutes (about 5 hours) instead of 150 minutes (about 2 and a half hours) per week. So, we’re starting to see the importance of physical activity.”

Christensen advises, “the sooner you start, the better and then you’ll build up. You can make quite large gains when you go from doing nothing to doing anything.”