Prayer is the most commonly used type of CAM; it's reported that nearly half of all Americans use some form of prayer in their lives. Researchers have recently begun to conduct studies on prayer to better understand if, and how, it may produce beneficial effects.

Researchers at the National Center for Complementary and Alternative Medicine (NCCAM) have seen some evidence that religious affiliation and religious practices are associated with health and mortality. What that means is that people with a spiritual connection may have a longer and healthier life. It may be that those who practice a religion have an effective way to cope with stress.

Prayer is an attempt to communicate with whatever you quantify as being greater than yourself, such as a deity, spirit, energy, or perhaps something you don't even label or identify. You may also look at prayer as a metaphor for hope. Typically, people pray for a positive outcome, such as good health or relief from a difficult situation. Prayer has a physiological effect on the body as it slows heart rate, lowers blood pressure, reduces stress and anxiety, and creates a sense of well-being. It can be done alone or in groups — in church with a prayer group.