The key to a good sex life may, indeed, lie in the heart—or at least the blood vessels it supplies. For most healthy people, the signs of sexual arousal—penile erections or vaginal lubrication—happen automatically. But both of these responses require a rich blood flow to the genitals. Cholesterol can build up in these blood vessels, as well as others in the body, impairing the function of these arteries and interfering with blood flow. 

In men, blood flow problems may result in an inability to develop erections. In fact, studies are finding that erectile dysfunction is often a marker of high cholesterol and arterial hardening, which is usually a "silent" condition. Some doctors argue that all men with erectile dysfunction should be screened for heart disease. A recent British study found that 18 of 20 men who had erectile dysfunction but no symptoms of heart problems actually had high levels of low-density lipoproteins (LDL, or "bad" cholesterol).

In women, the high cholesterol/sexual dysfunction link is less clear. However, in a new Italian study, women with hyperlipidemia, defined as high LDL, high triglycerides or low levels of high-density lipoproteins (HDL), were more than twice as likely to experience sexual dysfunction compared to those with normal lipid levels. The women reported lower arousal, orgasm, lubrication and satisfaction. Experts say that both men and women should discuss problems of sexual functioning with their physicians, and be sure that cholesterol screening is included in physical examinations.