If you train yourself to breathe from your stomach (so-to-speak) rather than from your chest, you significantly reduce the chances of contracting any type of bronchial infection. And, from personal experience, I've cured myself of about a half-dozen fevers, colds, and flus with a single (but good) meditation session. My guess is this is a result of increased oxygen intake, increased ATP generation, and a greater immune-system response. Also, it's been shown through PET scans (positron emission topography) that meditation enhances effective dopamine regulation and transmission in the body, which could plausibly be responsible for decreased stress and cortisol levels and a stronger immune system.