Exercise is usually OK if your signs and symptoms are all "above the neck" — symptoms you may have with a common cold, such as runny nose, nasal congestion, sneezing or minor sore throat. Consider reducing the intensity and length of your workout, though, or you may feel worse. Instead of going for a run, take a walk, for example.
Don't exercise if your signs and symptoms are "below the neck" — such as chest congestion, hacking cough or upset stomach.
Don't exercise if you have a fever, fatigue or widespread muscle aches.
Let your body be your guide. If you have a cold and feel miserable, take a break. Scaling back or taking a few days off from exercise when you're sick shouldn't affect your performance. Resume your normal workout routine gradually as you begin to feel better. And check with your doctor if you aren't sure if it's OK to exercise.
Remember if you do choose to exercise when you're sick, reduce the intensity and length of your workout. If you attempt to exercise at your normal intensity when you have more than a simple cold, you could risk more serious injury or illness.