Ancient Greek philosopher Aristotle viewed laughter as "a bodily exercise precious to health。" But 1 despite some claims to the contrary, chuckling probably has little influence on physical fitness. Laughter does 2 produce short-term changes in cardiovascular function and respiration, 3 boosting heart rate, respiratory rate and depth, as well as oxygen consumption. But because hard laughter is difficult to 4 sustain, a good guffaw is unlikely to have 5 measurable cardiovascular benefits the way, say, walking or jogging does。