Studies have found that regular, moderate exercise is effective for reducing one's risk of catching a cold. In a study of people with colds, exercise didn’t speed up recovery, it didn’t slow it down either. Unless there is fever or any serious problems, it appears the best medicine may be to continue exercising moderately while the cold runs its course.
From research published in the journal of the American College of Sports Medicine, click here to read a summary from the American Council on Exercise.
Information from ACE FitFacts, permission granted.