AYESHA RASCOE, HOST:
Exercise after COVID is frustrating for a lot of people and can be difficult for those with long COVID. A new study from the University of California, San Francisco looked at how this condition affects the ability of people to exercise. One takeaway - long COVID can dramatically reduce someone's capacity for physical activity. Joining me now is the co-author of this study, Dr. Matthew Durstenfeld. Good morning.
MATTHEW DURSTENFELD: Good morning, Ayesha. Thank you for having me.
RASCOE: Dramatically reduced - like, tell us what that means.
DURSTENFELD: Our study pooled together a lot of different studies that researchers have done looking at exercise and long COVID. And on average, we found a decrease of five milliliters per kilogram per minute. What that means is participants are exercising at the level they would a decade later in life.
RASCOE: So a decade later in life - like, when you say that, you mean that if you are 40, you will be exercising like you 50. On average, that's what you're finding.
DURSTENFELD: Exactly right.
RASCOE: What are the mechanics of that? Like, what is happening to the body that would cause something that dramatic?
DURSTENFELD: What we found was that there were a lot of different mechanisms. Some of it is due to deconditioning - decreased exercise from being sick - but there's a lot of other things going on, and deconditioning definitely doesn't explain it all.
RASCOE: OK. And so deconditioning means, as you said, it's - you haven't been exercising because you're ill and so then your body has to get back - used to activity.
DURSTENFELD: That's right. If it was all deconditioning, we could just advise people to exercise more. But we found other things, like decreases in oxygen in the muscles, a decrease in heart rate during exercise and dysfunctional breathing.
RASCOE: Do researchers have any idea how long it would take for someone to fully get back to pre-COVID fitness levels? I mean, when you start talking about losing a decade of your fitness capacity, that sounds so serious.
DURSTENFELD: Well, it is important that it's an average. So some people don't experience any decrease in exercise capacity, and other people experience a really profound decrease that really is debilitating. I think that another important point from these studies that we included is that they're all cross-sectional except for two, so they didn't really look at how things change over time. And the two that did, found that their exercise capacity did not return to normal when they repeated the studies months later.
RASCOE: That doesn't sound good. So looking at these studies - obviously, more studies probably need to be done - you're not seeing people get back to their pre-COVID fitness levels, on average.
DURSTENFELD: Right. I think we still need to know what happens to people. Do they get better on their own, or do they need some specific treatment for long COVID? We still don't have any treatments for long COVID, and so we really need to understand what's going wrong that's causing it in order to identify potential treatments to help people.
RASCOE: COVID is such a confounding disease. There's so much we still don't know about it. What do you think doctors and people who get COVID should take away from your team's findings?
DURSTENFELD: I think one is that decrease in exercise capacity is real and it can be objectively measured, and there's a lot of different reasons why someone could have decreased exercise capacity after COVID. And so for some people who that's a real issue for, it might be worth doing exercise testing and discussion with your doctor.
RASCOE: That's Dr. Matthew Durstenfeld with the University of California, San Francisco talking about exercise and COVID. Thank you so much.
DURSTENFELD: Thank you for having me. Transcript provided by NPR, Copyright NPR.
