The surprising secret to better sex

At parties they like to flirt with each other, arms entwined. Their body language says "passionate affair", not "married with children". You'd never guess that Tom and Sue Anderson are in their early forties and have been married for 17 years. 

A dozen years ago their marriage was solid but stale. Sex was pleasant but a little predictable. Then, after their second child was born, Sue began an exercise programme. As her figure improved, she felt more energetic and attractive. Impressed, Tom started running and working out and lost more than four stone. 

Now exercise at a local sports club has become a favourite pastime. And while they've been taking off the inches, romance has been taking off in their bedroom. As Sue puts it, "Sex is all brand new".

Common sense says that when you're feeling fit and attractive, intimacy is more appealing. But experts point to a host of physiological changes that may explain the "sexual second wind" that comes with moderate physical exertion. "Every system in the body works better when you're in shape," says Loren Cordain, lecturer of exercise physiology at Colorado State University.

A growing number of studies and surveys support the "sexercise" connection. Psychologist Linda De Villers analysed 2,000 responses to a questionnaire in a women's fitness magazine and found that 83 per cent of the women engaged in aerobic activity at least three times a week. Forty per cent said that, compared with how the felt before beginning their exercise programme, they were more easily aroused. Thirty-one per cent said they had sex more often, and 25 per cent reported climaxes came more easily. 

Almost any aerobic exercise can produce benefits in the bedroom. In a 1988 poll, 66 per cent of men and women runners claimed running made them better lovers. Best of all, the pay-off can come at any time in life. Reporting on his study of middle-aged swimmers, anthropologist Phillip Whitten concludes, "We found the sex lives of women and men over 40 who exercise regularly were similar to many in their late twenties and early thirties."

Experts are still debating why workouts prime us for passion. Some believe they may simply increase fitness. "People who exercise have more stamina," says Richard Reznichek, a urologist and sex therapist. Studies demonstrate that three one-hour sessions of moderate exercise per week can increase flexibility and strength, making you more limber in the bedroom.

Regular exercise may also boost sex by warding off the blues. Some scientists suggest that endorphins, released during exercise, may be mood-elevating. These "happy hormones" are naturally occurring opiates in the body, explains Dr Jay Schinfeld, a reproductive endocrinologist. In some people, they are released after about two miles of running or the equivalent and their effects can be felt for as long as three hours. 

Other researchers point to the cholesterol connection. Men who increase their levels of high-density lipoprotein (HDL) cholesterol may, over time, unclog arteries and increase blood flow throughout the body—including the pelvic region and sex organ. "A low blood supply", says James White, co-author of a study of the effects of exercise on sedentary men, "reduces male erectile ability".

Along with healthier hearts, many men and women who exercise develop a better self-image. Most of the women in Linda De Villers's survey reported a significant jump in sexual confidence with regular workouts. Swimmers in the Whitten study reported that they felt more attractive and had an increase in desire and satisfaction after several months of exercising. 

Luckily, a sexual boost can come with just a reasonable amount of effort, while very vigorous exercise can cause fatigue and dampen desire. Linda De Villers, who has created exercise programmes for couples, suggests these tips for a sexual jump start:

"Anyone who exercises and eats well," says James White, "will feel better and can have an abundant sex life."