covid19 · fitness

Physical activity and COVID risk: it’s complicated

This week, a new study came out, saying that people who were consistently inactive were more at risk for severe COVID effects– hospitalization, intensive care, and death– than people who were more physically active.

As usual, news sources here and here were anxious to promote what they saw as the take-home message: that if we want to avoid hospitalization and death from COVID, we all need to be consistently physically active (150+ minutes/week of moderate-to-vigorous activity).

Also as usual, I read through the study itself in detail, and found a lot of complications in the data and the analysis, which suggest a different take-home message (which I’ll get to shortly).

First though, the researchers and media coverage conveyed one message with one voice, loud and clear: physical activity is a strong modifiable risk factor for severe COVID.

Modifiable? What do they mean? They mean that our levels (and intensities) of physical activity are under our control– we have the option to increase or decrease the amount of time we spend on physical activity, as well as to change how vigorously active we are.

That’s clearly not true. And it’s not true on several fronts.

First of all, the researchers cite data that, on average, Americans have at least 4–6 hours a day of leisure time, which they tend to use on electronic media. That is, we’re sitting and playing with our phones or watching Netflix. The implicit conclusion is that we should instead be lacing up our sneakers and heading out the door instead.

But that’s just not the reality for most people. We know– from studies, from news, from talking with friends and neighbors, and from looking at our own lives– that the idea of work/life balance is a thing of the past. People are working longer hours and for lower wages and fewer or no benefits in the US and elsewhere. There may or may not be 4–6 hours a day in which people aren’t doing their jobs and aren’t sleeping (which is also rampantly in short supply for most). But there are the matters of childcare, eldercare, cooking, shopping for food and necessities, cleaning, paying bills, etc. You all know this.

So, in this sense, it’s not clear to me that people have at their disposal rafts of time for physical activity. And it’s certainly not uniformly distributed throughout the population. For instance, the researchers did NOT use income as a factor in their analysis. If they had, they might have had more interesting and useful results.

Second, let me dip into the data for a moment to show you another problem with this idea that physical activity is an entirely “modifiable behavior”. Take a look below:

Table showing the breakdown of study participants by level of physical activity.

What we see here is about 48K participants in total. Those who have been consistently inactive (0–10 mins/week) are 14% of the group. Those who are consistently active (150+ mins/week) are 6% of the group. The rest (80%) report 11–149 mins/week of activity.

The researchers are saying that, seeing that only 6% of the participants report meeting the national physical activity guidelines, that everyone else who isn’t meeting those guidelines must be failing to do so because of factors under their control.

That makes no sense to me– that they or anyone would draw that conclusion. We know that changing health behaviors around eating and activity is hard. We also know that many of these targeted health promotion campaigns tend to have pretty dismal long-term success rates. Why?

Because there are lots of structural features of our lives that make regular physical activity very difficult: time, access to safe spaces, nutrition, sleep, income, family and other obligations, physical and mental health conditions, ability/disability, you name it.

So, is physical activity a modifiable health behavior? Yes, sort of. But it’s much more complicated than the researchers are saying. Their recommendation:

We recommend that public health authorities inform all populations that short of vaccination and following public health safety guidelines such as social distancing and mask use, engaging in regular PA may be the single most important action individuals can take to prevent severe COVID-19 and its complications, including death.

My take on this: you can save your breath. We already know that physical activity is important. We’re not uninformed; we’re simply overburdened. It’s not your fault, researchers, but please stop saying in your conclusions that the public needs to be better informed. The public needs to be better served by government, health care, and places of work. Those are what I would call modifiable factors for quality of life.

4 thoughts on “Physical activity and COVID risk: it’s complicated

  1. Love this analysis. Thanks.
    I’ve got lots of physically active friends sharing stories about the study and I worry that about how it connects to blaming the ill for their illness, like if only they’d exercised more. I also worry that it’s feeding into a narrative from some gym owners that gyms ought to be open because it’s better overall for health. And finally I worry that some of these very physically active friends think they’re safe from covid because they’re in such good health. (They’re not. See our stories on the blog about athletes who’ve had covid-19.)
    Thanks for reading the original study and making clear what it does and doesn’t say.

    1. I also love the analysis, Catherine. You raise a lot of good points that might help avoid some of the self-righteousness and over-confidence Sam notes among already active people. The idea that everyone has 4-6 hours of leisure time every day and that they could easily hive off some of it for physically activity seems obviously false to me. I’m glad you articulated some of the reasons. Thanks for your post.

  2. Catherine, when I saw that headline in the NYT I thought, Oh boy, what ammunition will this become to blame individuals for structural issues. And my second thought was, I really hope Catherine tackles this one. Thank you for doing this so beautifully. I’m with Sam — I know super fit, super active people who’ve had long covid where they could barely walk up the stairs afterward for months. Being fit is not an alternative to AVOIDING getting infected. Which means no indoor gyms for the moment, people!

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