Researchers from Loma Linda University in California studied the cortisol, epinephrine (adrenaline) and dopac (a brain chemical that helps produce epinephrine) levels of male volunteers both before, during, and after a humorous event that they were anticipating. They found that cortisol was reduced by 39%, epinephrine by a whopping 70%, and dopac by 39%, even before the laughter began!
The same team studied the health effects of laughter two years ago in a similarly structured study that examined beta-endorphins (the family of chemicals that alleviates depression) and human growth hormone (HGS, which helps with immunity), and found that they increased by 27% and 87% respectively when subjects anticipated watching a humorous video. (The control group experienced no such increase.)
Dr. Lee Berk, the lead researcher from the team, said in a press release, "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."
I heartily agree! Laughter is one of my favorite stress relievers. And, even though my favorite kind is that side-splitting laughter that comes from spontaneous silliness that can't be planned, this research confirms that watching shows, videos and movies that you know will make you laugh can start relieving stress before you even begin watching them! Here's my list of favorite comedies if you need some inspiration. (And if you really crave that spontaneous, organic laughter that comes from life, check out these suggestions for having more fun in your life.)
Berk LS, Felten DL, Tan SA, Bittman BB, Westengard J. Modulation of neuroimmune parameters during the eustress of humor-associated mirthful laughter. Alternative Therapies in Health and Medicine, March 2001.