Can You Exercise When You’re Sick?
Does being sick mean you can’t stay fit? Find out the benefits and dangers of working out when you’re under the weather.
Ben Greenfield
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Can You Exercise When You’re Sick?
Just yesterday, cold weather forced me to put on a coat for the first time in a while, and as temperatures begin to dip, cold and flu season will set in. As a matter of fact, listener Eric recently asked:
“I’ve just come down with an obnoxious sore throat, accompanied with a lot of aches and chills. One thing I’m wondering is how should I exercise when I am sick? I obviously don’t want to go jogging in the cold, exacerbate symptoms, and make it harder to recover. But lying in bed, eating a lot, and getting fat is probably not the best approach either. I know that advice on this question would definitely depend on the severity of the illness, but are there some general guidelines?”
In this article, you’ll find out if you can exercise when you’re sick and what kind of workouts to do if you have a cold or flu.
Exercise Strengthens the Immune System
It’s a fact – regular physical activity strengthens your immune system. Studies have shown that recreational exercisers report fewer colds when they run regularly, and moderate exercise has been associated with a stronger immune system response and an increase in the production of macrophages, the cells that attack bacteria.
When you exercise, you improve blood flow and movement of your immune system’s lymphatic fluid, so your immune cells can circulate through the body more quickly to kill bacteria and viruses more efficiently.
The more consistently you exercise, the more immune system enhancement you can get. For example, one study has shown that people who walk at a very brisk pace for 40 minutes a day report half as many sick days as those who don’t exercise.
Can Exercise Make You Get Sick?
But you can certainly overdo it. For example, nearly every time I finish an Ironman triathlon, I get sick 5-7 days later – and research has shown that as few as 90 minutes of high-intensity endurance exercise can make you more susceptible to illness for up to 3 days after the session.
The reason for this is a release of certain hormones that can cause a temporary decrease in the proper function of the immune system. When you perform a hard exercise session, you significantly increase the release of cortisol and adrenaline, which are your body’s “fight and flight” stress hormones. This can raise blood pressure and cholesterol levels, and simultaneously suppress the immune system.
As you probably guessed, if you are already sick with a cold or respiratory infection, high intensity exercise such as heavy weight lifting or very long exercise such as marathon training can further weaken the immune system.
Can Exercise Make You More Sick?
But although high intensity exercise can make you more sick if you are already under the weather, moderate levels of physical activity are OK.
One study at Ball State University actually injected volunteer students with cold germs, then tracked them for 10 days, during which each participant logged their exercise sessions. In the exercise group that performed light aerobic activity for 40 minutes each day, there was no significant difference in cold symptom severity or duration.
So while the exercising group didn’t get better any faster, they also didn’t get any worse. But before you rush off to the gym to sniffle away on the treadmill, please remember that exercising in public places while sick may expose the rest of us to any contagious illness you may have – and it may be a better idea to simply go on a brisk walk outdoors or do some calisthenics in your living room.
When You Should Not Exercise
It is important to remember that exercising with a cold is much different than exercising with a fever or flu – which can not only make you more miserable, but potentially make you more sick. Fighting the flu requires nearly all the strength of your immune system, so and your illness may be aggravated by dehydration or muscle fatigue that occurs during exercise.
This is why nearly every physician will tell you: It’s OK to exercise if your symptoms are above the neck, such as a sore throat, nasal congestion, sneezing, or teary eyes. But if your symptoms are below the neck, such as coughing, body aches, fever, and fatigue, then you should give your body a chance for some much needed rest and recovery. Sometimes lying in bed really is the best course of action.
If you have more questions about exercising when you’re sick, share them below in Comments and on the Get-Fit Guy Facebook page!
Sick image courtesy of Shutterstock
About the Author
Ben Greenfield received bachelor’s and master’s degrees from University of Idaho in sports science and exercise physiology; personal training and strength and conditioning certifications from the National Strength and Conditioning Association (NSCA); a sports nutrition certification from the International Society of Sports Nutrition (ISSN), an advanced bicycle fitting certification from Serotta. He has over 11 years’ experience in coaching professional, collegiate, and recreational athletes from all sports, and as helped hundreds of clients achieve weight loss and fitness success.