Researchers at the University of Arkansas have come up with yet another reason for pumping iron. It can make you sexy, and even improve your sexual performance.
That may not seem particularly astonishing, especially since an abundance of research shows that regular exercise improves our physical fitness and makes us feel better about ourselves, but in fact there's not a lot of scientific evidence that it has much of an effect on our sexuality, according to the researchers.
Michael Young, professor of health science at the university, learned that fact a few years ago when he was asked to talk about sex and running fitness to athletes who were going to compete in a marathon the next day.
"The organizers assumed there would be a great deal of research on the topic indicating that runners and others who were highly fit would be more attractive sexually and be better performers, and that I would be able to organize and summarize that for the attendees," Young says. "But the research just wasn't there."
So, being a good scientist, he later asked a graduate student to see if she could correct that. Tina Penhollow, a doctoral candidate, lined up 408 volunteers on the university campus to see what they could tell us about physical fitness and sexuality.
Perhaps not surprisingly, she found evidence of a link between working out and both feeling sexually attractive and increasing sexual performance, but the results were not always consistent. It doesn't seem to work as well for women as it does to men, for example.
Men, for instance, thought they were sex gods in both attractiveness and performance if they worked out every day. But only 63 percent of the females in the study rated themselves as above or much above average in attractiveness and performance if they worked out nearly every day.
Why the difference?
"Guys and girls have a difference focus," Penhollow says. Guys do it mostly to "bulk up and get bigger," she says, whereas females do it mostly for health reasons.
She says it is more likely that women who work out obsessively have more of a problem with "body image" and are less likely to feel sexy no matter how good they may look.
But, generally speaking, the research partly confirms what Young concedes "we think we have known all along." Better physical fitness can lead to a better sex life.
That's consistent with scads of research showing that the better we feel, the more likely we are to engage in sexual activity, and exercise improves physical endurance and even encourages the flow of blood to the genital region. But does it really make us more sexually attractive, and does it really improve our performance?
The 408 college students who participated in Penhollow's study completed a 130-item questionnaire, mostly about health issues. But four questions focused specifically on exercise frequency, perceived fitness, perceptions of sexual desirability and sexual performance.
The participants remained anonymous in the study, which was published in a recent issue of the Electronic Journal of Human Sexuality.
Penhollow says the study confirms a link between exercise and sexuality, but it's not quite as clear as might be expected.
For example, more than 80 percent of the men who exercised two or three days a week view themselves as sexy, and all of the men who exercise six or seven days a week think they're sexy. But among those who work out four or five days a week, that percentage drops to 65.
Why the drop?
"I don't know," Penhollow says.
The study suggests it may have something to do with self-perception. Women who exercise four our five days a week, for example, were far less likely to rate themselves as physically attractive as those who worked out more or less.
What is clear, however, is those who think they're in poor physical shape also think they're not sexually attractive.
Some 60 percent of the males and 30 percent of the females who reported themselves as below average in fitness rated their sexual attractiveness as at least above average.
So Penhollow and Young say they've demonstrated that physical fitness really does play a role in our sex lives beyond the obvious gains of stamina and improved health. If we feel better about ourselves, we're more likely to regard ourselves as sexy.
However, it's worth remembering that this study consisted only of college students, and it's debatable as to whether they represent society as a whole, particularly when it comes to sex. Penhollow thinks they probably do, more or less, and the research she is conducting for her dissertation will extend to the general population.
Most of us probably think we already know the answer. But one function of science is to test the obvious. Sometimes, common sense is just dead wrong.
Lee Dye's column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.