Meditation is the practice of focusing attention on feeling calm and having a clear awareness about life. It can produce a state of relaxation that reduces heart rate, slows breathing, and lowers blood pressure.
Meditation usually involves slow, regular breathing and sitting quietly for 15 to 20 minutes. During meditation, a person may focus on a single image, sound, or mantra (words spoken or sung in a pattern). A person may focus on breathing. Some meditators do not focus on a single purpose but rather try to let all thoughts, feelings, sounds, or images just pass through their minds.
WebMD Medical Reference from Healthwise