According to LiveScience, researchers split 20 high-risk diabetic patients ~ all with hypertension and hyperlipidemia (a risk factor for cardiovascular disease) ~ into two groups. Both groups were given standard diabetes medication. One group, however, viewed 30 minutes of humor of their choosing, while the control group did not. (Note: Unfortunately the original article does not specify if the dose was daily, weekly or what.)
By two months into the study, the patients in the laughter group had lower levels of the hormones epinephrine and norepinephrine, both considered to be measures of stress. After the 12 months, good HDL cholesterol had risen 26 percent in the laughter group but only 3 percent in the other. In yet another measure, C-reactive proteins, a marker of inflammation and cardiovascular disease, decreased 66 percent in the laughter group but only 26 percent in the control group.
"The best clinicians understand that there is an intrinsic physiological intervention brought about by positive emotions such as mirthful laughter, optimism and hope," said study leader Lee Berk.
Click here for the LiveScience article.