Meditation is directed concentration, and involves learning to focus your awareness and direct it onto an object: your breath, a phrase or word repeated silently, a memorized inspirational passage, or an image in the mind's eye. Researchers have documented immediate benefits in terms of lowered blood pressure, decreased heart and respiratory rates, increased blood flow, and other measurable signs of the relaxation response. Even walking or sitting quietly in a natural setting "a simple form of meditation" is an antidote to being too focused on thoughts and emotions.
People who meditate regularly may find that the practice yields many subtle benefits. Over time, meditation may result in a restructuring of the mind that allows you to detach from the thoughts that cause emotional swings. It can even have the effect of leveling out mood cycles, and help you learn to do things more effectively - whether it is cooking, writing or martial arts. Overall, you may find that you become mindful - more aware of everyday aspects of your life - and able to bring more awareness to everything you do.
And of course meditation has beneficial effects on physical health. They include enhancement of immune function, lowering of blood pressure, and relief of chronic pain due to arthritis and other disorders. Results of a study published in the April 2004 issue of the American Journal of Hypertension showed that African-American teenage boys with high normal blood pressure were able to bring their blood pressure down over four months while they practiced transcendental meditation. The youths meditated for 15 minutes twice a day, and at times during the study wore ambulatory blood pressure monitors. After the study, the teens reported that meditating had benefited them in ways they hadn't expected: they found that they were better able to concentrate, felt less anger and noted improved relationships with others.
Andrew Weil, M.D.