It’s that time of year again—coughing, sneezing, and stuffy noses seem to be everywhere. When you feel the first signs of a cold creeping in, the big question often arises: Should you hit the gym or take a break? It’s tempting to power through with your usual workout, but experts have some strong advice about staying active during sickness.

Preventing Illness with Exercise

Let’s start with the good news: exercise can actually help prevent getting sick. Regular, light to moderate physical activity helps your immune system function at its best. Dr. David Nieman, professor of health and exercise science at Appalachian State University, explains that exercise helps the immune system recruit fighting cells from areas like the spleen and bone marrow. These cells circulate at a higher rate during and after physical activity, giving your immune system a boost.

This doesn’t mean you need to run marathons to stay healthy—simple activities like walking, swimming, or cycling for 30 to 60 minutes most days of the week will do the trick. However, the key is moderation. Intense or prolonged exercise can actually have the opposite effect, suppressing immune function and leaving you more vulnerable to illness.

Exercising While Sick: What’s Safe?

When you’re feeling under the weather, your body is already working overtime to fight off the infection, so adding a workout to the mix might not be the best idea. If you’re dealing with something serious, like the flu or COVID-19, experts recommend skipping exercise entirely. Dr. Nieman cautions against pushing yourself too hard—intense workouts when you’re sick could not only make you feel worse, but also prolong your symptoms.

However, if it’s just a mild cold, some light activity might be okay. Think of gentle movements, like stretching or a few bodyweight exercises. You won’t be curing the cold faster, but you might help your body stay limber and release some feel-good endorphins. Just remember, keep it easy—nothing that raises your heart rate too much.

Know When to Rest

When in doubt, it’s always better to rest. Dr. Nieman has worked with many patients who developed chronic fatigue-like symptoms from overexerting themselves while sick. If you’re not feeling up to it, your body is probably telling you to rest. Overdoing it can lead to longer recovery times, and in some cases, a condition called post-viral illness.

If you’re pushing yourself too much, your body might not be able to cope with both the illness and the strain from exercise. So, when sick, remember to listen to your body and take it easy.

Getting Back to Your Routine

Once you’re starting to feel better, don’t rush straight back into your usual routine. Wait until all symptoms are gone before jumping back into your workouts. Dr. Nieman suggests starting with something gentle, like walking, and gradually ramping up intensity over a couple of weeks. Similarly, Dr. Jamie Nuwer recommends waiting at least 24 hours after feeling better to go out in public, especially if you had an upper respiratory illness.

If you wear a fitness tracker, it can be a helpful tool to monitor your heart rate and gauge how your body is handling your return to exercise. Take breaks when necessary, and listen to your body as you get back to your fitness routine.

Final Thoughts

While exercising can help prevent illness when done in moderation, it’s important to give your body the rest it needs when you’re feeling sick. When in doubt, always err on the side of caution and rest up. Your body will thank you for it, and you’ll be back to your normal routine in no time!