Sometimes the Strongest Move Is Rest

This week I’m (finally) recovering from RSV, which has been a humbling reminder that even when you prioritize sleep, strength training, and nutrition, you’re still human. There was no “powering through” this illness; in fact, I haven’t been so sick since my first round of COVID. So instead, I’ve been leaning into rest, fluids, and patience, and thinking a lot about how best to support my body. Although exercise was out of the question for me for a full week (which is torture for me personally), I still think it’s important to understand if you should exercise when sick, or when to return to it after illness. Here’s what the science actually says about working out when sick.

There are peer-reviewed studies on exercise and immune function. Decades of research, including a well-known review in Medicine & Science in Sports & Exercise, describe what’s often called a “J-shaped curve.” Moderate, regular exercise is associated with a lower risk of upper respiratory infections. But very intense or prolonged exercise can temporarily suppress certain aspects of immune function, especially in already stressed or fatigued individuals.

A systematic review in the Cochrane Database looked at randomized trials comparing exercise vs. no exercise during acute respiratory infections (like the common cold). The evidence was considered low certainty, but moderate aerobic exercise did not appear to worsen illness and may slightly reduce symptom severity or total sick days in some cases.

The big picture:
While there’s no definitive yes-or-no answer to this question, science provides parameters we can follow.  

​​If your symptoms are mild and “above the neck” (think runny nose, mild sore throat, nasal congestion), then light to moderate movement (like walking, mobility work, easy cycling) is generally considered reasonable if you feel up to it.

But if you have:
• Fever
• Significant fatigue
• Chest congestion or productive cough
• Body aches
• Vomiting or diarrhea

That’s your cue to rest. Fever, in particular, is a hard stop, and exercising while febrile can increase the risk of dehydration and cardiovascular strain and delay recovery.

The bigger picture? Regular moderate exercise supports immune health over time. But when you’re acutely sick, your body is already doing hard work. Sometimes, the most physiologically smart training decision is recovery.

When in doubt, scale it down. And if you wouldn’t want the person next to you at the gym coughing like that, stay home.

(Note: there is an RSV vaccine that is recommended for everyone 65 years of age and over. When I tested positive, my husband rushed out to get his, as it had fallen through the cracks this year. Yes, that happens even to doctors’ families!)

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