Photo: flickr/scottYou know that you've wondered about it: how much of a workout is a roll in the hay? Well, so did these scientists, and to find out they had healthy couples wear exertion-measuring armbands while doing the deed. Lo and behold, they got a reasonable calorie burn--3.6 calories per minute--while gettin' frisky. (Although, as a friend pointed out, maybe the couples were working at it extra hard because they knew they were being "watched".) But that aside, at the measured rate, it would only take 16 hours of romping in bed to lose a pound of fat. The question is, if you're already spending 16 hours in bed, do you really care how much you weigh?Energy Expenditure during Sexual Activity in Young Healthy Couples "Objective: To determine energy expenditure in kilocalories (kcal) during sexual activity in young healthy couples in their natural environment and compare it to a session of endurance exercise. Methods: The study population consisted of twenty one heterosexual couples (age: 22.6 ± 2.8 years old) from the Montreal region. Free living energy expenditure during sexual activity and the endurance exercise was measured using the portable mini SenseWear armband. Perceived energy expenditure, perception of effort, fatigue and pleasure were also assessed after sexual activity. All participants completed a 30 min endurance exercise session on a treadmill at a moderate intensity. Results: Mean energy expenditure during sexual activity was 101 kCal or 4.2 kCal/min in men and 69.1 kCal or 3.1 kCal/min in women. In addition, mean intensity was 6.0 METS in men and 5.6 METS in women, which represents a moderate intensity. Moreover, the energy expenditure and intensity during the 30 min exercise session in men was 276 kCal or 9.2 kCal/min and 8.5 METS, respectively and in women 213 kCal or 7.1 kCal/min and 8.4 METS, respectively. Interestingly, the highest range value achieved by men for absolute energy expenditure can potentially be higher than that of the mean energy expenditure of the 30 min exercise session (i.e. 306.1 vs. 276 kCal, respectively) whereas this was not observed in women. Finally, perceived energy expenditure during sexual activity was similar in men (100 kCal) and in women (76.2 kCal) when compared to measured energy expenditure. Conclusion: The present study indicates that energy expenditure during sexual activity appears to be approximately 85 kCal or 3.6 kCal/min and seems to be performed at a moderate intensity (5.8 METS) in young healthy men and women. These results suggest that sexual activity may potentially be considered, at times, as a significant exercise." NCBI ROFL: When love makes you blind…literally. NCBI ROFL: What the f**k is a "placebo bra"? NCBI ROFL: Does watching TV lower your sperm count?