Should You Work Out When Sick? Your Guide to Exercising While Ill

Should You Exercise When Sick?

So, how helpful is this rule? “That rule is very simplistic, but unfortunately not useful,” says Lori Solomon, MD, chair of family and community medicine at New York Medical College in Valhalla, New York.

According to Dr. Solomon, the better question is not where your symptoms are occurring, but how poorly they’re making you feel. “I think it’s more reasonable to ask yourself what kind of movement you can do with your current symptoms and modify your workout if possible,” she says.

Solomon advises focusing on recovery, rather than beating yourself up if you don’t have the energy to exercise. In other words, it’s probably better to err on the side of caution than overexert yourself.

When to Skip the Gym

Some illnesses are gray areas when it comes to whether or not you’re okay to continue exercising, but experts say specific symptoms warrant skipping your workout. It’s best to lay low if you experience any of the following:

• Fever Don’t exercise if you have a fever or muscle aches. Fever limits muscle strength, thinking, and the flow of blood to the lungs, says Sarav Shah, MD, chief of the division of sports medicine at New England Baptist Hospital in Boston. Additionally, he notes that fevers can increase your dehydration risk during exercise.
• Flu, COVID-19, or Other Contagious Illness Is it safe to exercise with the flu or COVID-19? Maybe for you — but for the sake of others’ health, don’t work out in public if you have a contagious illness. “From an infection control standpoint, it’s best to not exercise in a public space so as to avoid spreading illness,” says Dr. Balogun. According to the Centers for Disease Control and Prevention (CDC), flu is contagious anywhere from one day before to seven days after symptom onset. 
• Severe Fatigue Colds and flu can make you tired and weak. When fatigue is severe, exercise can feel like an uphill climb. Listen to that inner voice that tells you you’re too tired to work out, Solomon advises. Ignoring it could prolong your recovery since exercise taxes your energy stores, potentially exacerbating fatigue.
• Chest Pain Chest pain is a signal to take it easy, says Balogun, especially if you have any underlying health conditions like cardiovascular or pulmonary issues. “These could be potentially exacerbated by working out,” she says.
• Difficulty Breathing Shortness of breath means you’re not ready for the gym. “Anyone with difficulty breathing through the mouth should skip their workout,” says Solomon. “If you’re getting short of breath or having difficulty breathing through the mouth, it could mean that there is an issue with the lungs.” See your doctor if you have swelling in your ankles, trouble breathing when you lie flat, high fever, or wheezing along with shortness of breath. 

Once you feel well enough to give exercise a try, ease in with these tips.

1. Lower the intensity. Don’t expect to pick up your workouts where you left off. In addition to symptoms such as runny nose and sore throat, you may feel deconditioned if you spent several days limiting physical activity. Plus, your body is still fighting whatever made you sick, so it can’t fully support your needs during and after exercise. To help your body recover, reduce your exercise intensity by 50 percent. Dr. Shah suggests keeping intensity down with an activity like yoga or Pilates. You can also try walking instead of running, or using lighter weights than you’re used to.
2. Increase intensity slowly. If you tolerate low-intensity workouts well, gradually increase the intensity. “A graded and gradual approach to exercise is safer to minimize the risk of injury or symptom aggravation,” Balogun says.
3. Avoid other people. Steer clear of indoor public spaces if you have a contagious illness like the cold, flu, or COVID-19. Instead, exercise on your own at home or outdoors. 
4. Stay hydrated. Exercise and illness can make you dehydrated, especially when you combine the two. Mild to severe dehydration can cause symptoms such as confusion, dizziness, headache, fatigue, muscle cramps, fainting, and rapid heartbeat. Prioritize hydration before, during, and after your workout. Also, avoid exercises and intensities that make you sweaty, as sweating a lot can make you dehydrated. 
5. Listen to your body. Before working out, check in with how you’re feeling. “If your symptoms are too much, it’s okay to skip your workout,” says Solomon. If you decide to exercise, pay attention to how you feel during the workout. Modify or stop the workout if your energy drops or your symptoms worsen. 

Besides listening to your body’s cues — and resting if you have any of the serious symptoms listed above — other indicators can tell you it’s safe to work out around others. “You should be free of a fever for at least 24 hours before returning to the gym,” Solomon says.

Talk to your doctor if you aren’t sure whether your symptoms are too serious for a workout. They can advise you on your best course of action.