It's that time of year, when colds and flu can knock us off our feet for a few days. Some people wonder whether they should try to keep up with their exercise or fitness program while they're ill.

Conventional wisdom says, "Let your body be your guide - it will tell you what to do." For example, people with a fever just don't feel well enough to exercise. According to one rule of thumb, if you're sick from the neck up (runny nose, sneezing), it's not necessarily a bad thing to exercise. But if you're sick from the neck down (body aches), you probably shouldn't work out.

The IDEA Fitness Association recommends these guidelines on when NOT to exercise:

• If you are extremely tired or have muscle aches, vomiting, diarrhea, chills, swollen lymph glands, or a hacking cough.
• If you have a fever - doing so increases the risk of dehydration, heatstroke, and even heart failure.

When you've recovered, return to exercise slowly - don't try to make up for lost time. Exercise at a lower intensity and work back up to your usual routine gradually. Give your body time to fully recover.

Related information Lifestyle changes - Exercise