How Long Will Your Love Life Last?

By midlife, you've probably discovered dozens of ways that men and women are different despite the egalitarian ideals of our youth. Now as we head toward old age, scientists have come with another fundamental difference between the sexes – the average length of time each gender stays sexually active. Spoiler alert: if you're female, you won't like it.

According to a study just published in the British Medical Journal, by the age of 55, men have an average sexual life expectancy of 15 years while women can expect only 10. The older you get, the bigger the gender gap. Among 75- to 85-year-olds, nearly 40 percent of the men surveyed were sexually active while only 16.8 percent of the women were, the researchers said.

Your overall health plays a major role in your ability to be sexually active. According to the study, which was conducted by researchers at the University of Chicago, people who were in generally good or excellent health were twice as likely to care about their sex lives as people with medical problems.

The researchers looked at samples representative of the U.S. population for their data, MIDUS (the national survey of midlife development in the United States, 1995-96) and NSHAP (the national social life, health and aging project, 2005-06). In all, they obtained information from more than 6000 adults.

In a study like this, it's hard to know what comes first: poor health or declining interest in sex. This is the kind of nuance that awaits further study. In the meantime, if you want to stay happy in bed, hit the gym.