People who meditate over a long period usually report that they feel calmer, happier and more able to deal with problems. These things aren't health benefits in themselves, but anything that leads to a reduction in stress levels is ultimately good for your health. Extensive meditation helps calm your heart rate and deepen your breathing, for instance, and practitioners tend to experience fewer stress-related headaches and similar illnesses.

The actual evidence for all this is rather hard to find. Yoga organisations and other meditation practitioners tend to claim a lot of direct health benefits, but if you look at the evidence it's not always clear-cut. However, recent studies show that meditation may have a beneficial influence on brain activity, and it's thought that very advanced meditators, such as some spiritual leaders, may develop permanent brain changes that make them calmer, happier (and therefore generally healthier) people. So there probably are health benefits in the end.