Experts worldwide believe that, by strengthening the heart, lowering blood pressure, improving circulation, stimulating the nervous system and boosting the immune system, laughter can be far more potent than many drugs.
In these times of ever-increasing pressure and workloads, it's easy to see how the mind can become over-loaded and stressed.
'Laughter stimulates production of the happy hormone, serotonin,' says Ben Renshaw, co-director of The Happiness Project. There is also evidence that it creates more endorphins which put us on a natural high, reduce stress and help us take on a more positive perspective.
Many experts believe laughter can significantly lower the likelihood of suffering a heart attack. 'Regular laughter lowers both your heart rate and your blood pressure,' says laughter therapist Dr Annette Goodheart.
It stimulates the whole cardiovascular system in a manner similar to exercise.
Laughter also suppresses the release of stress-related hormones. 'Mental stress is associated with the impairment of the endothelium, the protective barrier lining our blood vessels,' says Dr Michael Miller, of the Centre for Preventative Cardiology in Baltimore, USA. 'This can cause a series of inflammatory reactions that lead to fat and cholesterol build-up in the arteries.'
Laughter stimulates the respiratory system. It forces us to take in more oxygen and expel more carbon dioxide, which makes our breathing deeper and helps us relax. Some experts believe it may also increase lung capacity.
'Laughter can be used as a supplement to conventional treatment of respiratory diseases,' says Dr William Fry, one of America's leading researchers on the health effects of humour. 'It helps clear the bronchi of mucus and other infection-generated blockages.'
Anxiety, depression and stress weaken the immune system, leaving us susceptible to infection.
'Positive and negative emotions can trigger the release of neurotransmitters from neurons in the brain,' says Patty Wooten, of the American Association for Therapeutic Humour. 'These chemicals enter the blood stream and ''plug in to'' receptors on the surface of immune cells. When this occurs, that cell's metabolic activity can be altered in a positive or negative direction.'
Even the skin can benefit from regular laughter. When we laugh we take in more oxygen. The temporary increase in blood pressure and heart rate that results from laughter also causes the capillaries close to the skin to dilate in a similar way to when we exercise.
These capillaries become filled with blood which then feeds the skin with an increased supply of oxygen and nutrients.
Laughter can be a great way of exercising many of the muscles of the body. Research shows it's possible for almost all our muscles to be activated during laughter.
A belly laugh can exercise the muscles of the scalp, neck, torso, shoulders, arms, abdomen and legs and, although more research is needed, many experts believe that if it were to be sustained for an hour, it may burn as many as 500 calories.
'In fact,' says Dr Fry 'between 100 and 200 laughs a day is equivalent to ten minutes of rowing or jogging.'
Eva Fraser, of the Facial Workout Studio, believes that 'those who regularly exercise their face muscles can expect to delay middle-age sagging by ten years.'
'Laughter is a natural relaxant,' says Ben Renshaw. 'The increased production of serotonin helps release muscle stress or tension which may account for why a really good laugh can leave you feeling as though your body has turned to jelly.' ( dailymail.co.uk )