These doctors took blood samples at 10 minute intervals before, during and after the laughter workout. They found that humor and exercise trigger similar physiological processes. Laughter is one of the body's safety valves, a counter balance to tension. When we release that tension, the elevated levels of the body's stress hormones drop back to normal, thereby allowing our immune systems to work more effectively. Our natural killer cells increase in number and activity.
Laughter makes the entire orchestra more melodious or balanced.
In other words, laughter brings a balance to all the components of the immune system. In some clinics, scattered here and there throughout the world, laughter is beginning to take the place of anti-depressant drugs and reduces the need for pain killers. The physiological changes we discussed that occur with real laughter will also take effect even when we just pretend to laugh. Being unhappy or very sad can seriously damage your health. Chemicals in your brain make a plea for fuel, especially sweets.