A new study published in this month’s Journal of the American College of Cardiology found that erectile dysfunction (ED) is often an early indicator of poor cardiovascular health. Researchers followed more than 2,300 men for an average of four years and found that men with ED had a 58 percent greater risk of coronary heart disease.

The fact is, the very same habits that predispose a man (or a woman) to health problems, such as too little exercise, a poor diet, smoking and other lifestyle choices, also take a toll on sexual function. This study suggest that problems in the bedroom may be an important warning sign to shape up—if not for your sex life, then for your quality of life.

As we age, both men and women take longer to become sexually aroused, and may lose the urgency to have sex they once had. In men, waning testosterone levels can make a guy moody, irritable and depressed, as well as decrease his libido. In women, the hormonal changes of menopause may affect lubrication, arousal, orgasm, and, perhaps most significantly, sex drive.

But even so, the capacity to have satisfying sexual relationships does not disappear with age. We remain sexual throughout our lives, and many couples find that sex becomes more intense and intimate as they grow older. It’s not as simple as less hormones equals less sex. It’s all about lifestyle—exercise, diet, sleep, and a healthy engagement with life—and the quality of your relationship.

Sigmund Freud gave fantasy a bad name back in 1908 when he said, “A happy person never fantasizes, only a dissatisfied one.” Granted, this is also the guy who said clitoral orgasms were immature, and fortunately, we’ve had a century of research (and impassioned women) to prove Freud wrong.

The truth is, a healthy fantasy life is one key to a great sex life—and your partner might not always play the leading role. Fantasy isn’t the sad daydreaming of the lonely, forlorn or frustrated in love. Research shows that people with active fantasy lives are more sexually satisfied, more sexually responsive and more adventurous about sex in general. Not bad.