TUESDAY, Jan. 21, 2020 (HealthDay News) -- It might be the last thing you want to do when you are battling a cold, but exercise might actually make you feel better, suggests one health expert.

Here's why: Physical activity boosts your heart rate and promotes healthy blood flow, and it also opens up your lungs and releases endorphins, said Dr. Jayson Loeffert, a sports medicine physician at Penn State Health in Hershey, Pa.

If you feel tired sooner than normal, reduce your exercise intensity to what you can tolerate, he advised.

"If you are really congested or wheezing, you might be short of breath, so you'll want to decrease the intensity," Loeffert said in a Penn State Health news release.

Severe fatigue or uncontrolled coughing are indications that it's time to take a break.

Certain settings may pose challenges. Some people with colds may have trouble breathing when exercising outdoors in cold, dry air and may need to work out indoors until they're better, Loeffert said.

Also, swimmers with congestion may have more difficulty with their breathing, and the chlorine in a pool can make the congestion worse.

You shouldn't exercise if you have a fever.

"Exercise naturally causes an increase in body temperature. When you have a fever, your temperature is already higher than normal. If you have a fever, exercise can then cause your body temperature to be further increased to an unsafe level," Loeffert said.

If you have a cold and exercise in a gym or other shared spaces -- or share equipment -- always cover your mouth with your arm when you cough or sneeze, instead of spraying cold germs into your hands.

Wipe down all equipment with sanitizing gel or wipes when you finish using it.

More information

The American Lung Association has more on the common cold.