The average romp is equivalent to a short jog.
You don't need a scientist to tell you that sex can be a full-tilt, sweat-drenched workout. But how many calories does a good romp really burn? In a recent study, researchers at the University of Québec at Montréal measured energy expended during sex versus running, and found that we get our hearts pumping and muscles cranking enough during sex for it to be considered moderate exercise.
The researchers recruited 21 healthy, active, heterosexual couples in their early 20s to jog on treadmills at about 65 percent of their maximum heart rates for 30 minutes. While running, they wore lightweight armband monitors that measure energy expenditure in calories and exercise intensity in METs, or metabolic equivalent of task.
Next, the couples were asked to have sex once a week for a month while wearing the same armbands to track their calories and intensity during sexual activity. The duration of the sex varied, but the average session across all couples for the month was about 25 minutes.
On average, the men burned 9.2 calories per minute while jogging (or about 230 calories for a 25-minute jog) and had a mean intensity of 8.5 METs, compared to 4.2 calories per minute (105 calories per session) and 6 METs during sex. Women burned a little less, logging 7.1 calories per minute and 8.1 METs on the treadmill, and 3.1 calories per minute and 5.6 METs during sex.
Unsurprisingly, jogging for a half-hour taxed everyone's bodies more than having sex – but the researchers were impressed at how much energy these people exerted during sex. According to study author Antony Karelis, the participants burned enough calories and reached high enough intensities for sex to be considered "moderate intensity" exercise, the equivalent of walking briskly. While it's not on the level of doing wind sprints or 30-lap pool sessions, sex can be a legit form of exercise, says Karelis.
Sex is good for you, but it isn't always exercise: Karelis points out that sometimes sex isn't hot and heavy and doesn't always last long, so you can't count every quickie as a moderate workout. "Sex should not replace regular exercise," Karelis says. "Rather, sex and exercise should both be incorporated into your routine on a regular basis. Studies show that each improves health, so the combination of the two leads to a greater quality of life."