Women with more active sex lives may experience menopause later in life, according to the results of a 10-year study.
Published by the Royal Society Open Science, the study showed that women who reported weekly physical intimacy over a decade were about 28% less likely to experience menopause than women who reported less-than-monthly sexual activity.
The reason may be because "ovulation requires a lot of energy, and it has also been shown to impair your immune function. From an evolutionary standpoint, if a person is not sexually active it would not be beneficial to allocate energy to such a costly process," said Megan Arnot of the University College of London, the study's lead author.
"Doctors have long known that there were many benefits from continued sexual activity," said Dr. Jennifer Wu, an OBGYN at Lenox Hill Hospital in New York City.
"This study highlights a new finding: Women who do not engage in regular sexual activity go through menopause at an earlier age," said Wu, who didn't participate in the project. "With the earlier onset of menopause, patients experience more loss of bone and adverse cholesterol profiles."
The study doesn't explain the exact connection between sex and menopause, but it illustrates a possible association. Further studies would be required to establish stronger links.
The study began with a look at approximately 3,000 women -- 46% were peri-menopausal, meaning they had some symptoms, and 54% were pre-menopausal, meaning they had no symptoms. Over the 10-year study, 45% of the women began menopause, at an average age of 52.
The women studied were described as having sex weekly, monthly or less than month. Sex was defined as intercourse, oral sex, touching or caressing, or self-stimulation.
"It's the first time a study has shown a link between frequency of sex and onset of menopause," Arnot added. "We don't want to offer behavioral advice at this point at all. These results are an initial indication that menopause timing may be adaptive in response to the likelihood of becoming pregnant. More research will need to be done in the future."
Menopause often happens when women are in their mid-to-late 40s or early 50s. It occurs when the ovaries stop producing estrogen and progesterone, and menstrual cycles stop for 12 months. Many women experience hot flashes, fatigue, headaches or abdominal cramps. Some experience emotional difficulties as well.
John Smith, M.D., is a psychiatry resident from Medical University of South Carolina contributing to the ABC News Medical Unit.