If You: Give in to the giggles
You Will: Make your heart happy
Mom was right: Laughter really may be the best medicine. In a recent study, University of Maryland researchers discovered the endorphin surge generated by a good giggle prompts a release of nitric oxide — a protective chemical that fends off cell-damaging free radicals — inside the heart’s blood vessels. Not only does that lower your risk of having a heart attack, explains study author Michael Miller, M.D., but just 15 minutes of chuckling a day will do the trick!

If You: Picture it "pretty"
You Will: Halt hormonal havoc
Repeated research has found that visualization can trick the brain into soothing the body — a special boon when hormonal fluctuations have you on a less-than-even keel. ""Picturing an image that evokes the idea of balance — a scale, for instance — sends a calming message to the limbic system, the emotional center of the brain,"" explains Holly Schwartztol, Ph.D., a Miami-based psychologist. "The limbic system then forwards that message to the pituitary gland, which regulates the body’s hormones." (Studies show that creative visualization can actually ease moodiness and cramps in as few as 30 seconds!)

If You: Think good things
You Will: Starve a cold
Looking on the bright side can actually keep sniffles and sneezes at bay. Scientists at Pittsburgh's Carnegie Mellon University found that people with positive attitudes were much less likely to develop cold symptoms than glass-half-empty types. Probably because, as Jacob Teitelbaum, M.D., author of From Fatigued to Fantastic!, explains, "being pessimistic elevates levels of the stress hormone cortisol, which can hinder the body’s production of infection-fighting white blood cells.""

If You: Just say "om"
You Will: Perfect your pulse rate
When you’re stressed out, and in "fight or flight" mode, your body releases epinephrine and norepinephrine — hormones that increase blood pressure. But slow, deep breathing — or even the steady repetition of a single word or sound — can lower it fairly quickly, says Herbert Benson, M.D., director of the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital. In fact, experts at the University of Kentucky found that people who practiced meditation on a regular basis lowered their blood pressure by as many as five points.

If You: Groove to the tunes
You Will: Get better zzz’s
Listening to soothing music before bed can enhance your quality of sleep by 35 percent, say Taiwanese researchers. Soft music (classical or jazz, for instance), especially, has proved to lower the body’s stress hormone levels, slowing heart rate and improving breathing patterns, explains Dr. Teitelbaum. The combined effect can help you transition from a light, fitful sleep to one that’s deep and rejuvenating.