Cardiovascular responses to laughter: a pilot project.

The purpose of this study was to determine cardiovascular responses to laughter. The CO(2) rebreathing method was used to determine cardiac output and understand the role of the central and peripheral components of oxygen consumption and its relation to energy expended. Eight college-age subjects participated in this study. During periods of 5 minutes each, while sitting in a comfortable chair, subjects first rested, then viewed a videotape of a well-known comedian, then remained sitting. A repeated-measures analysis of variance was used to analyze the data. During laughter, there were significant increases in stroke volume and cardiac output and significant decreases in arteriovenous oxygen difference and total peripheral resistance. Following laughter, there was a significant decrease in oxygen consumption. Copyright 2000 by W.B. Saunders Company