Studies on the human lifespan and health of laughing found that people with a strong sense of humor live longer despite having the disease, especially cardiovascular disease and infection.

Norwegian researchers reported the findings of a 15-year study on the link between sense of humor and mortality among 53,556 men and women in their country. The team evaluated the cognitive, social, and emotional components of humor using a validated questionnaire.

The findings show that high scores on the cognitive component of humor for women are associated with a 48 percent lower risk of death from all causes, a 73 percent lower risk of death from heart disease, and an 83 percent lower risk of death from infection. A link was found only for the risk of death from infection in men. Those with high humor scores had a 74 percent reduced risk. The authors suggest that gender differences may be due to a slight decline in humor scores as men age. No relationship was found for the social and affective components of humor.

Laughing at a funny movie might seem like an activity with little consequence for health, but research shows that the 20 or so facial muscles involved in laughter do more than exercise. According to this research, laughter is among the latest studies showing that humor and happiness play a key role in health and longevity and can positively affect various diseases and conditions such as high blood pressure, flu, heart disease, arthritis and diabetes.

The concept that laughter is good for you is also used in therapy to improve quality of life, provide some pain relief, encourage relaxation, and reduce stress. Some centers now provide some form of humor therapy. One in five National Cancer Institute treatment centers in the US positions units in treatment centers that provide opportunities that can be combined with exercises such as yoga, which include watching movies, listening to tapes, reading books, or attending humor workshops.

It has long been recognized that low mood, including depression, can have a negative impact on physical health. For example, patients who become depressed during heart bypass surgery are more than twice as likely to die within the next five years. Stress chemicals triggered by extreme stress can also double the chances of death from heart disease or stroke.

Studies show that laughter and humor can have a positive effect on health and longevity. Happiness and laughter have been shown to increase natural cell activity in the blood and free radical scavenging capacity in saliva, and lower levels of the stress hormone cortisol. It is also thought that laughter causes the release of specific neurotransmitter substances in the brain, such as endorphins, that help control pain. There are also more direct physical effects of laughter, including more breathing, more oxygen use, and higher heart rate.

Some research suggests that laughter can boost the immune system. Researchers at Japan's Osaka University School of Medicine found that when they showed a group of men and women a funny 75-minute movie, blood levels of cell activity increased by 26.5 percent.

HAPPY MARRIAGE KILLS THE FLU!

Happiness also boosts the immune system. A study conducted at the University of Birmingham found a link between high levels of antibodies to the flu and a happy marriage. Those with the highest marital satisfaction had higher antibody responses to the flu vaccine after four weeks. A second study conducted at the University of North Carolina shows that happiness in marriage is linked to lower blood pressure and less stress hormones.

A study by the International Foundation for the Advancement of Science, also in Japan, showed that laughter lowers the levels of a protein that plays a role in the progression of diabetic nephropathy, a kidney disease that occurs as a result of diabetes and is its primary cause. Levels dropped significantly right after watching a comedy show. "The beneficial effects of laughter in preventing the flare-up of diabetic nephropathy are strongly suggested," the researchers say.

But one of the most important findings regarding the effects of laughter is its effect on inflammation, a component of many age-related chronic diseases that play a key role and often cause a wide range of diseases from arthritis to cancer. The research, reported in the Oxford University Press Medical Journal of Rheumatology, showed that patients with rheumatoid arthritis had significantly reduced blood levels of important inflammatory compounds after watching a humorous movie.

According to the researches done so far, we talked about the positive effects of smiling on human health and psychology.