Is It OK to Work Out When You're Sick? Here's How to Tell

Some gym fans like to boast that they never, ever skip a workout even when they're not feeling 100 percent. That's some serious dedication! But it's not always advisable. Though there are some cases when it's OK to work out sick, chances are, it's best to take a rest day (or several).

Exercise has plenty of health benefits, but if you're fighting an illness, your body needs time to recover properly. And if you push yourself too hard in the gym, you may prolong the time it takes to get better.

How do you decide if you should you suck it up or throw in the towel? You'll need to consider your symptoms first.

Is it bad to work out when you're sick? The answer largely depends on what symptoms you're experiencing and their severity. First, assess how you're feeling overall. If you feel like you need a rest day, take it! Just like one workout won't give you six-pack abs, skipping one or two gym sessions won't set you back.

Illness can lead to fatigue or dehydration — two big things to look out for when weighing the decision to work out, as exercise can make these symptoms worse, says Cynthia Li, MD, who owns a private practice in integrative and functional medicine. While fatigue and dehydration may not be severe, they may be signs you should skip your workout, she says.

Generally, though, if your symptoms are "above the neck," you're probably OK to exercise, according to the Mayo Clinic. However, if you feel "below the neck" symptoms, you'll want to skip your sweat session.

It's OK to exercise if your symptoms are above the neck:

• Sore throat
• Runny nose
• Nasal congestion

It's best to avoid exercise if your symptoms are below the neck:

• Fever
• Chills
• Muscle aches
• Chest congestion
• Coughing
• Stomach pain

Still not sure? Consider Dr. Li's advice for some common ailments:

Generally, Dr. Li advises against exercising with a cold, instead prioritizing rest to conserve energy and recuperate as quickly and efficiently as possible. However, it's generally not dangerous to exercise with a cold if your symptoms are limited to your eyes, nose and throat.

Bottom line: Listen to your body. If you don't feel well enough to exercise, don't.

Typically the flu is accompanied by a fever or feverish chills, muscle or body aches and (for some people) digestive unrest, according to Harvard Health Publishing. While most people recover in a few days, it's important to give your body plenty of rest, as the flu can develop into other conditions, like pneumonia, if it persists. So, plan to skip your workout and stay in bed.

"Someone with the full-blown flu usually finds it challenging to walk to the bathroom, so I think it's highly unlikely she or he would consider exercising," says Dr. Li.

Usually, a stomach bug indicates your digestive system is, shall we say, disturbed, which means you're probably losing a lot of fluids, according to the Mayo Clinic. In some cases, a stomach issues may also come with a fever and muscle ache.

Considering the potential for dehydration, you definitely want to skip your workout if you're dealing with a stomach bug, Dr. Li says. Especially if you're experiencing a lot of vomiting or diarrhea, you'll want to be wary of your hydration levels and see the doctor one to three days after infection (or the onset of symptoms).

If you're dealing with a respiratory infection in your chest, Dr. Li recommends avoiding exercise until your cough and congestion completely subside before going back to the gym. Respiratory infections can make breathing difficult, which can be especially taxing if you're planning get your heart rate up with some exercise.

As with any sickness, it's important to avoid infecting others after testing positive for COVID. While you're sick and experiencing symptoms, take a total break from the gym and exercise in general, according to a January 2021 report in the BMJ.

After you get through at least 7 days symptom-free, you can gradually begin to get back into exercise. But, the report recommends starting with two weeks of minimal-exertion movement. Stick to easy walks or relaxing yoga flows. Then, so long as your body feels good, you can slowly get back into more challenging workouts.

If your symptoms return after you start exercising, it's best to stop working out completely and see a medical professional.

Even if you ‌feel‌ well enough to exercise, going to the gym when you're sick is inconsiderate (and harmful!) to those around you. For the common cold, symptoms usually persist over several days, whereas flu symptoms can develop within a few hours. Generally, people are contagious for about a week after symptoms develop.

Whether you're dealing with a cold or flu, steer clear of the gym for at least a week to protect those around you. That's because respiratory infections, like the flu and common cold, are mostly spread through aerosolized droplets, Dr. Li says.

When you sneeze or cough, those droplets enter the air and can get into the mouth or nose of a gym-goer nearby. Or, these droplets can land on the equipment around you, which can be transmitted to the person who uses the machine next.

Don't tough it out at the expense of your fellow exercisers. "Home is where you should be when you're sick," Dr. Li says. "Avoid touching your face, cover your cough and sneezes with a tissue, keep your distance from others and wear a mask when possible."

One last — and very important — reminder: "For anyone with an upper respiratory infection: Wash or sanitize your hands frequently," Dr. Li says.

Although rest should be the main priority if you're not feeling well, if you still plan on going to the gym while sick, you'll want to adjust your workout, Dr. Li says. Dial down the intensity and length of your workout. Instead of going for a run, bring your pace down or opt for a walk. Avoid intense intervals and keep your workout short.

Before you decide to work out at all, though, remember that exerting yourself while sick can slow your recovery time. No one wants to stay sick longer than they need to, so if possible, consider a few days off for optimal recovery.

Should you decide to hit the gym, be considerate of your fellow gym-goers. Wash your hands regularly, wipe down your machines and use a personal water bottle instead of the water fountain. Though you really shouldn't exercise if you're contagious (it's not fair to everyone else), even these small measures can help prevent the spread of germs.