Is it safe to exercise when you’re sick? The answer depends on your symptoms and how sick you’re actually feeling. You can figure this out by using the “neck rule.” If you have symptoms above the neck—such as a sore throat, nasal congestion, sneezing, or (seasonal) allergy-like symptoms—then exercise can actually be good for you. Moderate exercise is a natural decongestant and can help make it easier to breathe if you’re feeling stuffy.
If your symptoms are below the neck—including a deep or productive cough (one where you cough up mucus), chest congestion, fever, fatigue, or body aches—then rest until the symptoms are gone. A stomach bug is also a reason to sit it out due to risk of dehydration from vomiting or diarrhea. If you have a fever—a temperature of 101°F or higher—moderate or vigorous exercise generally isn’t safe because it can increase your risk of dehydration and heat-related illness as well. Consider skipping your workout if there’s any chance you might infect others too.
If you’re too weak and tired to get out of bed or have a fever, exercising might not be the best choice. But, if you only have symptoms of a head cold and your temperature is below 101°F, light to moderate exercise could be good for you. Remember to wipe down or use a spray disinfectant on any gym equipment you use—and wash your hands!
Make sure to see a doctor if your symptoms don’t improve after a few days or get worse.
Edward R. Laskowski, M. D. (February 9, 2017). Is it OK to exercise if I have a cold? Retrieved from https://www.mayoclinic.org/healthy-lifestyle/fitness/expert-answers/exercise/faq-20058494
Olson, L. G., & Strohl, K. P. (1987). The response of the nasal airway to exercise. American Review of Respiratory Disease, 135(2), 356–359.
Purcell, L. (2007). Exercise and febrile illnesses. Paediatrics & Child Health, 12(10), 885–887. doi:10.1093/pch/12.10.885