- Researchers have conducted the first systematic review on the physical demands of sexual intercourse.
- They found that a bout of sexual intercourse burns an average of 100 calories and raises the heart rate to between 90 and 130 beats per minute.
- The popular missionary position is actually the most demanding position on the lumbar spine, increasing the risk for lower back pain.
Most of us might not think of sex as exercise, but a recently published systematic review finds that it could count as “moderate intensity physical activity,” about as strenuous as light jogging, leisurely swimming, or stationary rowing.
Researchers from the University of Almería spearheaded the literature review, which is published in the Archives of Sexual Behavior. Lead author José M. Oliva-Lozano and his colleagues searched for any and all published experiments investigating the physical demands of sexual intercourse. They found 18 studies published between 1956 and 2020, with a total of 349 participants (264 men and 85 women). Though these studies differed in their exact methods, the researchers behind them invariably asked subjects to engage in real or simulated sex in a variety of positions while measuring physical exertion in terms of heart rate, blood pressure, and oxygen use. They also gauged stresses on various muscles and joints.
Sexy time metabolism
Reviewing the findings, Oliva-Lozano and his colleagues found that a bout of sexual intercourse generally burns around 100 calories, but this value varies widely as the average time people have sex also differs greatly. A recent study asking more than 500 couples to measure their average intercourse time returned a range from 33 seconds to 44 minutes, with a median time of 5.4 minutes.
Oliva-Lozano and his team also found that mean heart rates during sex range from 90 beats per minute to 130 beats per minute, starting lower during foreplay before accelerating and peaking at up to 170 bpm at orgasm. A normal resting heart rate for adults ranges from 60 to 100 beats per minute.
Unsurprisingly, lumbar spine flexion and extension from repeated, back-and-forth hip thrusts was the most common source of stress on the body. The demands on the spine were actually greatest in the missionary position for both men and women, perhaps the most common sexual position, with the most stress on the person “on top.” “Doggy-style,” where the receiving partner rests on hands and knees and the penetrating partner stands or kneels behind, might actually be the best position to minimize bodily stresses, particularly on the lower back.
Shoulder injuries can also frequently occur during sex, a risk of any position in which the thrusting partner has to prop themselves up with locked arms at the shoulder joint.
The researchers noted a few key limitations of the published research. Notably, most of the studies only explored the physical effects of sex for men, and the vast majority just looked at heterosexual couples. Moreover, somewhat surprisingly, only six studies had been published in the past ten years, suggesting an open opportunity for researchers to use modern technologies to more accurately measure the bodily demands of sexual intercourse.