Although physical activity can help boost your immune system, people who are sick should tone down their workout or skip it altogether, experts advise.

“Regular exercise is a great way to reduce stress and sleep better at night. This helps boost your immune system. However, vigorous exercise and extreme conditioning can have a negative impact on your health if you’re sick,” Joe Berg, a personal trainer and fitness specialist at Loyola Center for Health, said in a Loyola University news release.

“When fighting a viral illness, it’s best to keep your exercise session short and not as intense. If you have a fever or stomach bug it might be best to hold off,” Berg added.

For those recovering from an illness, it’s best to ease back into a workout routine slowly. Berg recommends starting small with some light aerobics, such as walking and cycling at an easy pace as well…