Collateral damage.

Looking for motivation to eat a healthy diet and stay physically active (or encourage your husband to)? If avoiding a heart attack or stroke or diabetes isn't reason enough, the next sentence should do it.

"The same risk factors that damage blood vessels to the heart can also damage blood vessels to the penis, and if these are damaged, erection will not occur normally," says cardiologist Robert Kloner, director of research at the Heart Institute of Good Samaritan Hospital in Los Angeles. "Lipid abnormalities, smoking, diabetes, and high blood pressure raise the risk of both heart disease and ED."

In fact, "erectile dysfunction may be an early warning sign for heart disease, especially in men over 40 or 50 years of age," says Kloner. Men with erectile dysfunction (ED) are twice as likely to suffer heart attacks as men without ED, according to a recent analysis of the health records of more than 25,000 U.S. men. (1)

In a study of his male patients with coronary artery disease (their average age was 64), Kloner and his colleagues found that three-quarters had trouble achieving or maintaining erections. (2)

And men who had no chronic medical conditions and who exercised, didn't smoke, and didn't drink excessively had the lowest rates of erectile dysfunction among the more than 31,000 participants in the Health Professionals Follow-Up Study at the Harvard School of Public Health. (3)

"Unfortunately, we don't have enough information about whether the risk of ED can be reversed by lowering your risk factors for heart disease," says Kloner.

That's because no one has done a study. But researchers have tested the impact of weight loss and exercise on ED.

"Four studies show that if you exercise you can lower your risk of ED," says urologist Irwin Goldstein of the Boston University School of Medicine. "Exercise promotes the health of the endothelial cells lining the arteries, and that lowers the risk of impotence."

And in a 2004 study, 17 of 55 obese men with ED regained their sexual function after losing an average of 33 pounds over two years and walking about 30 minutes a day. Only three of 55 similar men who didn't lose weight or become more active overcame their ED. (4)

What about women? "Cardiovascular disease definitely, substantially affects sexual function in women," says Goldstein. "But we don't have as much evidence about this as we do for men because the research is just emerging."

Now are you ready for that brisk walk?

(1) Int. J. Impot. Res. 16: 350, 2004.

(2) J. Urol. 170: 546, 2003.

(3) Ann. Intern. Med. 139: 161, 2003.

(4) J. Amer. Med. Assoc. 291: 2978, 2004.