In the early 1970s, Dr. Herbert Benson, president and founder of the Mind/Body Medical Institute at Harvard Medical School, documented a phenomenon he dubbed “the relaxation response” which he says is the opposite of the body's fight-or-flight mechanism.
Benson experimented using Sanskrit mantras. He told his subjects to sit quietly and repeat the prayer either mentally or verbally for ten to twenty minutes, to breathe regularly and to push intruding thoughts aside as they entered their minds.
Benson found that those who repeated the Sanskrit mantras, for as little as ten minutes a day, experienced physiological changes—reduced heart rate, lower stress levels and slower metabolism.
Repeating the mantras also lowered the blood pressure of those who had high blood pressure and generally decreased the subjects' oxygen consumption (indicating that the body was in a restful state).
Subsequent studies documented in Benson's Timeless Healing found that repeating mantras can benefit the immune system, relieve insomnia, reduce doctor visits and even increase high-school sophomores' self-esteem.
Benson and his colleagues also tested other prayers, including “Lord Jesus Christ, have mercy on me,” and found that they had the same effect. Even words like one, ocean, love and peace produced the response.
It appears that Benson and his colleagues had uncovered a universal principle: repetitive prayer allows human beings to enter a relaxed state.