Stress can drain your immune system, which increases your risk of getting sick. (Don't believe it? In one 2012 study, published in the Proceedings of the National Academy of Sciences, people who experienced a major stressful event were two times more likely to catch the common cold.) So think of “chilling out” as just another exercise for your workout routine, which can help keep your body strong. Dr. Eliaz suggests yoga and Tai Chi, but meditation and counseling can also help.