Laughter has a positive impact on vascular function
From the page: “Watching a funny movie or sitcom that produces laughter has a positive effect on vascular function and is opposite to that observed after watching a movie that causes mental stress according to research conducted at the University of Maryland School of Medicine in Baltimore, Maryland.
“The idea to study positive emotions, such as laughter came about after studies had shown that mental stress caused blood vessels to constrict”, says Dr. Michael Miller, Professor of Medicine and lead investigator.
In their initial study more than 10 years ago, 300 men and women with or without heart disease completed a questionnaire related to situational-humor. For example, if you went to a party and saw someone wearing the same clothes as you, on a scale of 1 to 5 (ranging from not funny at all to very funny) how would you respond? The volunteers with heart disease were 40% less likely to find these situations funny. Even though this study was unable to prove whether a humorous response to situations in daily life may protect against heart disease, (or the lack of such a response is more common after a heart attack), it led to the next series of studies testing whether laughter may directly affect vessel function.
In this manner, volunteers watched segments of a funny movie, such as “There’s something about Mary” on one day and on another day watched the opening segment of the stressful movie “Saving Private Ryan”. Each volunteer served as his or her own control.
When study volunteers watched the stressful movie, their blood vessel lining developed a potentially unhealthy response called vasoconstriction, reducing blood flow. This finding confirms previous studies, which suggested there was a link between mental stress and the narrowing of blood vessels. However, after watching the funny movie, the blood vessel lining expanded. ”