We’ve heard it all before: Sex is a workout. But although many have made reference to it — primarily through jokes — it turns out that sex could actually be just as good as running on a treadmill for 30 minutes, according to a new study. What’s more, it’s also (not surprisingly) so much more enjoyable.

Sexual activity proved to be a great workout for both men and women. However, men saw the most benefit, burning 4.2 calories per minute compared to women, who burned 3.1 calories per minute. Men and women burned more than as many calories by spending 30 minutes on the treadmill, with 9.2 calories per minute and 7.1 calories per minute, respectively. But even though they used up less energy during sex, the level of intensity was almost two-thirds that of treadmill exercise. “Taken together, these results suggest that sexual activity may potentially be considered, at times, as significant as exercise,” the researchers wrote.

The study is one of the first to use SenseWear armbands, a non-obstructive piece of equipment that allowed researchers to monitor energy expenditure and intensity without hindering the normal intimacy involved in sexual activity. Previous studies had used facial masks used to measure oxygen intake, which contributed to the “environmental and methodological limitations,” to say the least.

Twenty-one heterosexual couples, ages 18 to 35, were recruited for the study. They participated in a moderate-intensity treadmill exercise for 30 minutes. The U.S. Department of Health and Human Services’ Physical Activity Guidelines for Americans recommends 30 minutes of moderate-intensity aerobic activity at least five times a week.

Each participant was given a SenseWear armband, which measures energy expenditure through heat sensors, accelerometers, and galvanic skin response sensors, and was told to have sex once a week while wearing the armband. After each sexual encounter, the participants answered a questionnaire about their and their partner’s perception of sex compared to treadmill exercise, the amount of calories they think they burned, and the amount of effort they put into each activity, among other things.

Not surprisingly, 98 percent of participants felt that sex was more pleasant than treadmill exercise, while 81 percent reported a high level of personal pleasure. The average duration of sexual activity was 24.7 minutes, and ranged from 10 to 57 minutes. Men burned an average of 101 calories, while women burned 69 calories during sex. The researchers also found that those who lasted the longest could burn more calories during sex than while running on a treadmill, burning 306 calories compared to 276 calories, respectively.

If that’s not enough to convince you that sex has its health benefits, consider these 10 other reasons, or just look for inspiration in this former world’s heaviest woman, who began losing 14 lbs. each month from sexathons with her ex-husband.

Source: Karelis A, Levy J, Toupin I, et al. Energy Expenditure during Sexual Activity in Young Healthy Couples. PLOS One. 2013.