http://www.guardian.co.uk/science/st...745532,00.html
Laughter really is the best medicine
Alok Jha, science correspondent
Monday April 3, 2006
The Guardian
It might be regarded as a statement of the obvious. But scientists have proved what everyone else takes for granted - that laughter really is good for you. It turns out that even the anticipation of watching a funny video can raise the levels of immune-boosting hormones in the blood and the benefits can last up to a day.
Lee Berk of Loma Linda University found that people expecting to watch a funny movie had 27% more beta-endorphins and 87% more human growth hormone hurtling around their blood compared with a control group. He will present his work today at a meeting of the American Physiological Society.
"We believe the results suggest that the anticipation of a laughter eustress [positive stress] event initiates changes in neuroendocrine response prior to the onset of the event itself," said Dr Berk. "From our prior studies, this modulation appears to be concomitant with mood state changes, and taken together, these would appear to carry important, positive implications for wellness, disease-prevention and most certainly stress-reduction."
The researchers studied 16 healthy men, split into two groups. In one group, the volunteers had chosen a favourite video to watch. All participants had blood samples taken just before the experiment began and then during and after the video. The second group acted as the control experiment.
"One of the keys in this kind of experiment is to set the baseline and control environment carefully," said Dr Berk. "In this case, the control group basically sits in a neutral room waiting to have their blood drawn, and on the tables there is a wide variety of magazines that they can browse, because you don't want to bias what they do or watch. Time and behaviour have proved me right with this approach."
The strong difference in hormone levels between the two groups was maintained from just before the beginning of video watching, throughout the viewing and afterwards too.
Dr Berk said that laughter diminished the secretion of the body's stress hormones, cortisol and epinephrine, while enhancing immune response. "In addition, mirthful laughter boosts secretion of growth hormone, an enhancer of these same key immune responses. The physiological effects of a single one-hour session viewing a humorous video has appeared to last up to 12 to 24 hours in some individuals."
Previous experiments have shown that watching comical videos can offset the symptoms of long-term stress, a condition that is known to weaken the immune system's response to viruses and tumours.
Dr Berk concluded: "It may sound corny but we in the health care medical sciences need to get serious about happiness and the lifestyle that produces it, relative to mind, body and spirit. Why do you think Reader's Digest has claimed that laughter is the best medicine for so many years?"