Researchers led by Antony D Karelis from University of Quebec at Montreal conducted their study on a group of 21 young, heterosexual couples. They first measured the participants' energy expenditure during a 30 minute jog on a treadmill. The participants were then sent home after being fitted with arm bands so as to measure the energy spent during sexual activity over the next four weeks.
The researchers found that the MET (metabolic equivalent of task) score during sex was 6 for men and 5.6 for women. This score is equivalent to that of walking uphill or playing doubles tennis while the MET scores for jogging was higher at 8.5. The participants were also asked to fill out a questionnaire in which they were asked whether sex or jogging was more fun, with almost all choosing sex apart from two percent who thought jogging was more fun.