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It’s that time of year again. We’ve transitioned from the joy and celebration of the holidays to the unwelcome arrival of cold and flu season. Influenza cases are spiking, RSV is making its rounds, and Covid-19 is creeping back into the mix. For the past few years, we’ve all been extra cautious and maybe kept germs at bay. But the reality is that illness is an inevitable part of life, no matter how careful we are.
For runners, sickness can feel catastrophic. Plus, we are a unique breed—often determined to power through a stuffy nose or lingering cough to keep logging miles. If you’re wondering whether you can “sweat out” a fever or outrun a cold, here’s the hard truth: you can’t. Pushing yourself by running while sick can slow down your recovery.
So, if you’re considering running while your immune system is under siege, here are three things to consider.
Don’t Run With a Fever
A general rule of thumb is to take time off from training when you have symptoms below the neck (sore throat, cough, body aches) and definitely if you have a fever. If you feel a cold coming on, taking an extra rest day shouldn’t hinder your training progress. And even several rest days won’t affect your fitness level. (Seriously, you likely won’t lose fitness unless you’re out for more than 10 days.)
We get it, though. It can be hard to take time off from running (especially if you’re in a training cycle where it seems that every run is critical). But pushing through illness can be downright dangerous. Running with a fever is especially harmful because the of the disruption of temperature regulation and fluid balance. Plus, fevers diminish muscle strength, aerobic capacity, and coordination.
“The body has to shift gears and focus on [the run] and it puts a lot of stress on the body, particularly the heart,” says Dr. Carrie Jaworski, a board-certified physician in family and sports medicine. “That doesn’t necessarily cause myocarditis, but it does put the heart under stress and cause the heart to have to work harder which could then cause arrhythmia and other cardiac conditions could be uncovered because of it.”
Sometimes, Running While Sick Is OK
If you have mild symptoms that are localized only to your head (think congestion or sinus-related symptoms), an easy run might be fine. “If your symptoms are above the neck and you feel up to it, you’re not completely drained and tired, then it’s reasonable to exercise,” says Jaworski. But if you feel worse after your run, that’s a sure sign that you need more rest.
RELATED: Help! My Ears Hurt While Running in the Cold
Good judgement is paramount here. Even if you think you’re well enough to get your run in, it’s probably better that you take a break. Translation: if there’s any doubt in your mind, kick back, relax, and recover fully.
Eat, Drink, and Be Smart About Nutrition
It’s easy to become dehydrated when you’re sick for physiological and behavioral reasons. Your body is burning calories and using metabolic reserves to fight off the infection, which can dehydrate you. This is especially true if you have a fever, says Jaworski.
When you’re sick, hydrating is not always top of mind. When you’re too tired to leave your couch or bed, you might not be refilling your water bottle as often as you would if you are up and moving around. Fill up a few water bottles at once, make yourself plenty of herbal tea, and make sure you’re sipping throughout the day. Of course, if you’re not getting out from under your blankets, you’re likely not planning to run anytime soon. But for those of you with mild symptoms or those coming back to running after a week or so off, make sure you’re hydrated before you start.
RELATED: Getting Back to Running After the Flu
Adding extra vitamin C and zinc into your diet with foods that are high in it can also be helpful in keeping your immune system supported. “There’s been some studies that say zinc is helpful,” says Jaworski. And though that research is still relatively new, it couldn’t hurt to eat some extra zinc-rich foods to try and shorten your recovery time.
Foods that are high in vitamin C:
- Red and green peppers
- Oranges and orange juice
- Grapefruit
- Broccoli
- Strawberries
- Brussels sprouts
- Tomato juice
- Cantaloupe
- Cabbage
- Cauliflower
- Potatoes
Foods that are high in zinc:
- Oysters
- Crab
- Pork chops and pork loin
- Baked beans
- Pumpkin seeds
- Yogurt
- Cashews
- Chickpeas
Know When to Call Your Doctor
If any cold or flu symptoms persist, check in with your doctor. If you have any cardiac-related symptoms come on while running, that is also a sign that you need to see an expert. “[If] you start developing shortness of breath, more than just being tired and winded from working hard, or you develop any heart palpitations (any funny heart beats or irregular feeling in your chest, whether that be chest pain or irregular heart beats), wheezing, anything more substantial should absolutely prompt you to stop and get further evaluated,” says Jaworski.
Remember, there’s no shame in slowing down. In fact, sometimes that’s exactly what the body needs.