This One Silly Trick Can Accurately Tell Someone’s Body Count

Your grip strength might be doing more than helping you open jars. A new study from Washington State University found that people with stronger upper bodies tend to report more sexual partners. This pattern showed up in both men and women, which throws a wrench into the usual theories about strength, sex, and evolution.

Researchers pulled data from over 4,300 adults in a national health survey and compared it to grip strength measurements. That number, often used to estimate upper body strength, turned out to have a surprising link with lifetime partner count. Stronger people had longer sexual histories.

“Regardless of whether they’re males or females, stronger individuals have more lifetime sexual partners,” said Ed Hagen, an evolutionary anthropologist at WSU. “That was a surprising finding and somewhat contrary to the sexual selection hypothesis.”

Your Upper Body Strength Might Be Predicting Your Body Count

That theory has long suggested men evolved to be stronger because they had to compete physically for mates. But if strength also tracks with women’s partner count, there’s something else at play. The study’s lead author, Caroline Smith, pointed out that physical strength may have helped men do more than win fights.

“Besides acquiring more sexual partners, establishing long-term relationships was likely also important for men in evolutionary history,” Smith said. If you could hunt, carry, and protect, you had better odds of sticking around and being seen as a reliable mate.

For women, the explanation is a bit murkier. Theories range from strong women taking more risks to assortative mating—where fit people tend to choose other fit people. The study controlled for hormone levels and overall health but the connection still held.

There’s not one neat answer here, which is kind of the point. Most of the science around this topic has focused on men, leaving women out of the equation (surprise, surprise). But this study suggests upper body strength could matter across the board—and for different reasons than we’ve assumed.

“I believe it’s important to continually test our theories, especially by expanding our research questions to include women,” Smith said.

You could hit the gym for your health. Or, based on this, you could do it for science, sex, and a better grip on your love life.