Answered by Janet Lee on Monday, June 1, 2009
Let's put it this way: If you're planning to make sex a part of an already active lifestyle, great. But if you're relying on it to lose weight or tone up, you'd need to spend hours a day in the sack. According to the energy expenditure tables compiled by exercise physiologists and found in the Health and Fitness Instructors Handbook (Human Kinetics), sex burns anywhere from 60 to 120 (the lower range for foreplay and the upper range for particularly vigorous sex) calories an hour for a 130-lb. woman and 77 to 155 calories an hour for a 170-lb. man. Considering that running burns around 600 calories an hour, you can see that sex is not the most efficient mode of weight loss. In fact, foreplay takes about the same amount of energy as sitting around on the couch, and a more rousing session that might wake up the neighbors is still only the equivalent of a slow walk. But really, who's counting?