As summer comes to an end, flu and cold season is rapidly approaching. While you may be speeding steadily along on your workout schedule, and rarely missing a day, chances are that you may, at some point this fall or winter, be sidelined with some kind of illness.

I often see a lot of clients at the Diversified Health and Fitness gyms wiping their noses and coughing into their hands. While it’s not a bad idea to work out while slightly under the weather – say, a mild cold – there are some general guidelines to whether or not you should work out or just sit it out until you feel better.

So let’s say you feel like you’re coming down with something. This can vary from anything to a slight cold to a flu. Some experts think that if you even feel something coming on, you should avoid working out and go home and rest – if you’re sick, your body is trying to tell you something.

Perhaps you think you can make it to the gym that day, though. Maybe it’s just a little tickle in your throat, a little hacking cough. Working out with a mild cold is probably ok, most experts agree. And it can be hard to want to miss a day when you’re really feeling like you can do it.

If you’re running a fever, however, it’s best to skip the gym. Working out puts more stress on the heart, which is already beating faster due to your higher body temperature. If you’re taking certain kinds of medication, your heart rate can also increase, and combined with exercise, this can be dangerous. And if you’re suffering from chest congestion or a cough, or shortness of breath, it’s definitely better to skip your workout. I think it also goes without saying that if you have stomach flu symptoms, you’re probably not going to want to step foot in the gym either.

A lot of people mistakenly believe that exercising while working out sweats out the “toxins” in your system, and can actually help you get rid of a cold or flu faster. This is completely false, as toxins in your system do not leave your body through your sweat glands. Working out while sick can often prolong your illness as well, as your body doesn’t need the extra stress and should be using its energy reserves to fight off the illness.

When you’re feeling good enough to make it to the gym again, make sure you don’t go 100% your first time there, even if you’re really tempted to. I had a client today at Butterfly Life that recently got over the flu, and today we focused only on 10 minutes of light cardio (walking on the treadmill), some light weightlifting, and stretching. Next week, when she’s feeling even better, we’ll get back into her normal, intensive routine.

Exercise is great for boosting your immune system, it’s true. But when an illness comes on, listen to your body and take care of yourself! It’s not worth making yourself even sicker just so you don’t miss a workout.