Public Release: 

Expecting a laugh boosts stress-busting hormones

Study finds expectation of humor has a biological effect on body

University of California - Irvine

Irvine, Calif. -- Go ahead, laugh. In fact, look forward to the upcoming positive event. It does the body good.

Yes, even looking forward to a happy, funny event increases endorphins and other relaxation-inducing hormones as well as decreases other detrimental stress hormones, a UC Irvine College of Medicine-led study has found.

In previous studies, the scientists found that anticipating a funny video reduced feelings of stress. This study found that those feelings have biological underpinnings and may help researchers combat the harmful effects of stress. The study was presented at the annual meeting of the Society for Neuroscience in Orlando, Florida.

Lee Berk, assistant professor of family medicine and a researcher at the Susan Samueli Center for Complementary and Alternative Medicine, and his colleagues found that just anticipating a funny event reduced levels of stress-causing chemical messengers in the blood, and increased levels of chemicals known to reduce tension.

"Since chronic stress can suppress the immune system's ability to fight disease, reducing the effects of stress can help the body resist infections and other disorders," Berk said. "This study shows that even knowing you will be involved in a positive humorous event days in advance reduces levels of stress hormones in the blood and increases levels of chemicals known to aid relaxation. This has profound implications for complementary treatment of disease and for maintaining a person's wellness."

Berk and his colleagues tested 16 men at Loma Linda University. Half of them were informed three days in advance they would watch a humorous video. The men watching the video had a 39 percent decrease in cortisol, a 38 percent drop in dopac and a 70 percent drop in epinephrine, all of which are stress hormones. At the same time, endorphin levels rose 27 percent, and growth hormone levels rose 87 percent. Endorphins and growth hormones are known to reduce the effects of stress and benefit the immune system. These changes were not seen in the other eight men who were told they would not view the funny video.

The levels of stress-inducing hormones increasingly dropped (and for the stress-reducers, rose) at a progressively greater rate as the date of the humorous experiment approached.

Previously, Berk and his team found that anticipating a funny video changed the subjects' mood states. In addition, Berk has shown that watching humorous videos decreased some stress hormones and increased the activity of specific white blood cells called natural killer cells that specialize in killing virally infected cells and tumor cells.

"The anticipation of a funny event changes mood states, which appears to trigger profound physiological changes in the body," Berk said. "These mood and body changes also lasted well after the actual event. Optimism and expectation or anticipation of positive experiences appear to help in recovery from illness, supporting the reality that there may be a biology to the concept of hope." Berk and his colleagues continue to look at the relationships between mood, behavior and prevention and effective treatment for a wide range of diseases.

Berk's colleagues in the study include Dr. David Felten, executive director of the Susan Samueli Center for Complementary and Alternative Medicine, and Dr. Stanley Tan of the Oakcrest Research Institute and James Westengard of Loma Linda University School of Medicine.

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