Immune System

Regular physical activity helps boost the immune system and keeps your defenses strong, so your body can fight off those nasty, illness-causing germs. But don’t go to the opposite extreme by putting your couch potato body through the rigors of a daily boot-camp workout. Working out too strenuously can actually wear you down so you’re more susceptible to colds.
Elite athletes and marathoners know too well just how easy it is to get sick when you’re overtraining. Instead, aim for a happy medium, like walking briskly 30 minutes a day. Not only is it sustainable and enjoyable, it will help keep your immune system primed to fight against invaders, so you can hopefully get through the winter cough- and sniffle-free.