It looks like that old column in Readers Digest was right. According to a study published in the journal Heart, laughter really is the best medicine! Researchers speculating that positive emotions may have a beneficial impact on a person's health have shown experimentally that watching comedy films boosts blood flow to the heart. After an overnight fast that included abstinence from alcohol, vitamins, herbs (Cheech & Chong were always laughing) and aerobic activity, researchers randomly assigned 20 healthy young adults to view 15 - 30 minute segments of either tearjerkers or comical films.
"Because cinematic viewing evokes a range of negative and positive emotions, the present study was designed to compare the effect of mental stress versus laughter on endothelial function," said the study's authors. Comprised of a thin layer of flat cells that line the interior surface of blood vessels, the endothelium covers the entire circulatory system and plays a vital role in blood circulation. "Because the time course of the effects of laughter or mental stress on endothelial function has not been established, a minimum of 48 hours elapsed between the two arms of the trial," say the authors.
The films used to illicit either tears of joy or misery from their square-eyed subjects included Saving Private Ryan and There's Something About Mary. In all, 160 measurements of brachial artery blood flow were taken before and one minute after phases of laughter or sadness. The brachial artery runs from the shoulder to the elbow, and is a good indicator of general blood flow circulating around the body.
Brachial artery blood flow was reduced in 14 of the 20 participants after watching movie clips that caused distress. But it was increased in 19 of the 20 participants after watching movie clips that elicited laughter. The difference in flow between sad and happy responses exceeded an astonishing 50 percent.
The extent of the impact of watching a sad film was of the same magnitude as remembering episodes of anger or doing mental arithmetic, said the authors, while the impact of watching a funny film was equivalent to a bout of aerobic exercise or starting on statin treatment (used to lower cholesterol levels in people at risk of cardiovascular disease). The authors conclude that their data raises the possibility that while negative stressful environments reduce optimal heart function: "positive emotions such as mirthful laughter have an opposite effect on the endothelium."
While the study was never intended to test and understand the mechanisms involved, the authors speculated that, "such effects may be attributable to attenuation of neuroendocrine hormones involved in the downregulation of endothelial dependent vasodilatation." Well, ahem, of course that makes perfect sense; now I'll go back to watching Godzilla vs Mothra.
Source: British Medical Journal - Specialty Journals
