The concept is actually not new.notably in Madan Kataria's laughter yoga movement practiced by thousands of people worldwide.Sixteenth-century humanist educator Richard Mulcaster said that because laughter produced warmth in the body, it might be a good remedy for colds.Other scientists of his time noted that laughter increased the rate of breathing, boosted muscle

tone, and exercised the body's internal organs.So although many physicians and medical researchers had long thought that laughter could be helpful, scientific studies had been inconclusive.Although no one can state definitively that laughter cured Norman Cousins, the concept of laughter therapy has gained popular acceptance.Then, in his classic 1956 book The Stress of Life, Hungarian scientist Hans Selye wrote, based on extensive research, that he had proved that biological stress has negative effects on health.They claimed that those effects were beneficial to people suffering from colds too.