Hi, Everyone,
A new study involving over 50,000 participants suggests that regular exercise protects against severe COVID-19 infection.
The study, which was published in the British Journal of Sports Medicine, found that those who had exercised the most leading up to contracting SARS-CoV-2 were least likely to be hospitalized or die from the infection.
The study looked at records from patients in the Kaiser healthcare system in California, in part because Kaiser doctors ask patients questions about how much they have exercised recently during each visit.
The researchers then stratified the subjects into groups based on the amount of time they had exercised (defined as equivalent to or greater in intensity than a “brisk walk”) in the past week:
- Least active: 10 minutes or less
- Most active: 150 minutes or more
- Moderately active: in between least and most
The findings were striking. Those in the least active group were 2.5-fold more likely to die than those in the most active group and 30 percent more likely to die than those in the moderately active group.
What’s more, the only other risk factors for severe COVID-19 that had a greater impact than physical inactivity were advanced age and organ transplants.
The caveat to this study is that it was observational—so we can’t be certain that it was the exercise itself, and not some other characteristic that people who exercised more shared, that explained the results.
However, there are two reasons to believe that exercise is, in fact, the causal factor here. First, we know from decades of research that exercise promotes better immune function in numerous ways. Second, the study authors controlled for several potential confounding factors, including age, smoking habits, weight, and history of diabetes and other pre-existing conditions.
This study, along with previous research I’ve shared on vitamin D, squarely contradicts the dominant public health narrative, which seems to suggest—whether implicitly, by omission, or explicitly—that there’s nothing we can do to protect ourselves from COVID-19 other than maintaining social distance and getting vaccinated.
In fact:
- Those who are mostly inactive physically have a 2.5-fold higher risk of death from COVID-19 compared to people who exercise 30 minutes a day.
- Those who are deficient in vitamin D have a 1.77-fold higher risk of infection, a 2.57-fold higher risk of more severe infection, and a 2.35-fold higher risk of death (according to a recent meta-analysis).
These are not small differences—they’re hugely significant. And they are likely additive, meaning that if you both exercise and maintain normal vitamin D levels, your risk of a severe COVID-19 outcome will be even lower than if you did either one of these alone.
And yet, where is the public health campaign reminding people to exercise, maintain normal vitamin D levels, engage in efforts to lose weight, and take other steps to improve their overall health and immune function—along with interventions like distancing and vaccines?
Where, indeed?
In health,
Chris
P.S. Between chronic disease, depression, loneliness, COVID-19, and more, we are at a crossroad of multiple health epidemics—many of which stem from the mismatch of our current environment and our biology. In my most recent podcast episode with co-authors Dr. Robert Barrett and Dr. Louis Francescutti, we discuss the influence of evolution and how it affects all aspects of our behavior. Their most recent book, Hardwired: How Our Instincts to Be Healthy Are Making Us Sick, really got my attention.
