The SenseWear bands use accelerometers, temperature sensors and galvanic skin response sensors to come up with an accurate measurement of calories expended. Galvanic skin response refers to an increase of electrical conductivity that occurs when a person sweats.
Let's get physical The recorded sex sessions lasted for an average of 24.7 minutes, with the shortest lasting 10 minutes and the longest stretching out over 57 minutes. Men expended more energy getting busy than women, even after controlling for men's greater body mass. On average, a sexual encounter cost men 101 calories, or 4.2 calories per minute. That's compared with 276 calories, or 9.2 per minute, on the treadmill.
Women expended an average of 69 calories during a session of sex, averaging 3.1 calories per minute. Again, the numbers weren't as high as a sweat-it-out session on the treadmill, during which women expended an average of 213 calories, or 7.1 per minute.
Still, the researchers said, people found sex pleasant (duh) and thus might be more likely to get horizontal than to schlep to the gym. Sex may also be a better way to burn calories than housework, though more research is needed: A study released in October in the journal BMC Public Health found that people overestimated how many calories they were burning while sweeping floors and vacuuming.