Women may not need a guy, a vibrator, or any other direct sexual stimulation to have an orgasm, finds a new study on exercise-induced orgasms and sexual pleasure.

The findings add qualitative and quantitative data to a field that has been largely unstudied, according to researcher Debby Herbenick, co-director of the Center for Sexual Health Promotion at Indiana University. For instance, Alfred Kinsey and his colleagues first reported the phenomenon in 1953, saying that about 5 percent of women they had interviewed mentioned orgasm linked to physical exercise. However, they couldn't know the actual prevalence because most of these women volunteered the information without being directly asked.

Since then, reports of so-called "coregasms," named because of their seeming link to exercises for core abdominal muscles, have circulated in the media for years, according to the researchers.

"Despite attention in the popular media, little is known scientifically about exercise-induced orgasms," the researchers write in a special issue of the journal Sexual and Relationship Therapy released in print this month. [5 Myths About Women's Bodies]

Pleasure at the gym

Herbenick and her colleagues used online surveys to gather their data, which included answers from 124 women who had experienced exercise-induced orgasms and 246 women who reported exercise-induced sexual pleasure. Most of the women, ages 18 to 63 and an average age of 30, were in a relationship or married and 69 percent said they were heterosexual.

The researchers found that about 40 percent of both groups of women had experienced exercise-induced pleasure or orgasm on more than 11 occasions in their lives. Most of the women in the "orgasm" group said they felt some level of embarrassment when exercising in public places.

The "orgasm" group mostly said during the experiences they weren't having a sexual fantasy or thinking about someone they were attracted to.

Of the women who had orgasms during exercise, about 45 percent said their first experience was linked to abdominal exercises; 19 percent linked to biking/spinning; 9.3 percent linked to climbing poles or ropes; 7 percent reported a connection with weight lifting; 7 percent running; the rest of the experiences included various exercises, such as yoga, swimming, elliptical machines, aerobics and others. Exercise-induced sexual pleasure was linked with more types of exercises than the orgasm phenomenon.

Abdominal exercises may be best

Answers to open-ended questions in the survey revealed some interesting details, the researchers found. For instance, the abdominal exercises tied to orgasms seemed to be particularly associated with the exercise in which a person supports their weight on their forearms on a so-called captain's chair with padded arm rests and then lifts their knees toward their chest.

The open-ended questions also revealed the orgasms tended to occur after multiple sets of crunches or some other abdominal exercise rather than after just a couple repetitions; they also seemed to happen after the woman had really exerted herself.

"Many of these women talked about it happening even as children," Herbenick said during a telephone interview, adding that some indicated an experience at age 7 or 8.

"We had at least one woman in the study who was a virgin, and she really loved that she could have these experiences at the gym," Herbenick said. [10 Surprising Sex Statistics]

The researchers aren't sure why certain exercises lead to orgasm or sexual pleasure, though Herbenick hopes to tease out the trigger in ongoing research.

"It may be that exercise, which is already known to have significant benefits to health and well-being, has the potential to enhance women's sexual lives as well," Herbenick said, adding that it isn't clear whether these exercises could actually enhance women's sexual experiences.

Learning about the 'Big O'

The research has various implications regarding women's sexuality. For one, orgasm and sexual desire have topped women's list of sex concerns, with around one out of four women not reaching orgasm during sex. The researchers suggest "it may be that physical exercise has been overlooked in clinical approaches to women's orgasm."

Second, scientists have long debated the evolutionary context of the female orgasm and its link to sexuality and reproduction. However, if many women are experiencing orgasm during exercises not related to sex, then exercise-induced orgasm may reveal what orgasm does and does not have to do with sex or reproduction, the researchers note. [G-Spot: Science Can't Find It]

In addition, exercise-induced orgasms may be one way for scientists, and women themselves, to learn about the process of orgasm. "It may be one way for women to learn more about how their bodies work in that regard," Herbenick said.

As for how other scientists may react to the finding: "I think from having talked with colleagues, while some people have heard of these [exercise-induced orgasms], many of our colleagues haven't either," Herbenick told LiveScience. "So I think that's going to be interesting," seeing the reaction. She added that some might question, "'Is this a tooth fairy type of thing or does it really happen?' I have no doubt that it happens."

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