I Have a Cold. Should I Work Out?

by Jason Bosley-Smith, CSCS, FDN
Lifestyle Coach, Live Well @ LifeBridge

The question of whether or not you should work out when sick is one that I often get from clients and one that is somewhat disputed amongst doctors and exercise physiologists. The question is often whether exercising when ill will make you worse, or as some people claim, help “kick the cold out” of you.

Researchers at Ball State University tested a group of athletes, some infected with rhinovirus and another control group that were not, to measure their response in lung function, exercise capacity and symptoms. When their symptoms were at their worse two days later, the subjects exercised on treadmills at moderate to intense levels. To the researchers’ surprise, lung function was not inhibited nor was basic metabolic response. General questionnaires were also provided to the subjects. Most said their symptoms were no worse and a few even mentioned feeling better.

This study was conducted on subjects with a basic head cold with mild symptoms of runny nose and sneezing. The researchers cautioned that while it may be OK to exercise under these conditions, individuals should be wary of exercising while having any illness that brings fever, chest congestion, or other symptoms below the neck.

Another factor to consider in this equation is that of hormonal response; namely cortisol. Cortisol is a stress-response hormone that provides anti-inflammatory benefits and is in essence our “fight or flight” hormone. While exercise is extremely beneficial to the body, it is still a stressor, albeit a positive one, and as such, results in the release of cortisol. Cortisol, although necessary and helpful in some regards, can have a negative effect on the body and in this scenario; it is its impact on immune function that is the key. Cortisol has an immunosuppressive effect, meaning that if your body constantly has high levels of cortisol, you are more susceptible to illness or infection. Since the obvious goal when you’re sick is to have your immune system working at full capacity to heal and eliminate the virus or bacteria that are causing the illness, it may be counterproductive to exercise and release cortisol.

All in all when you are sick, the goal should be to listen to your body, get adequate rest, and eat clean, whole, nutritious foods. This will let your immune system do its job and help you feel better quickly.