MONDAY, April 7, 2008 (HealthDay News) -- Anticipating a good laugh reduces the release of stress hormones that can weaken your immune system over time, according to a new study.
The researchers, who previously had found that the build-up for mirthful experience boosted health-protecting hormones, suggested that mirth may be a key to better physical and mental health.
"Our findings lead us to believe that by seeking out positive experiences that make us laugh, we can do a lot with our physiology to stay well," the study team's lead researcher, Lee Berk of Loma Linda University in California, said in a prepared statement. The study was scheduled to be presented Monday at the annual meeting of the American Physiological Society during the Experimental Biology 2008 scientific conference in San Diego.
In their earlier work, the researchers found that two "beneficial" hormones -- depression-alleviating beta-endorphins and immunity-boosting human growth hormone -- increased when volunteers anticipated watching a humorous video.
Using a similar protocol, this time they studied 16 healthy, fasting male volunteers assigned to either a control group or a group told to anticipate a humorous event. Blood draws from both groups were taken before the event (anticipation), during the event and afterward, then analyzed for three hormones associated with stress. Chronically released high-stress hormone levels can weaken the immune system.
The levels of the stress hormones cortisol, epinephrine (also known as adrenaline) and dopac -- a brain chemical that helps produce epinephrine -- fell by 38 percent to 70 percent during the anticipation stage in the group told they would be having a humorous experience. A progressive pattern of decreased levels for the three hormones occurred throughout the event.
The U.S. National Library of Medicine has more about managing stress.