Moderate exercise may help prevent impotence, or as it has come to be known thanks to the makers of Viagra, erectile dysfunction, according to researchers.

In a large, long-term study, researchers found that men who burned at least 200 calories a day through exercise were less likely than inactive men to become impotent.

• Over the course of about 9 years, researchers followed nearly 600 men who initially had no problems with impotence.

• The researchers focused on lifestyle factors believed to contribute to impotence:
  • smoking
  • heavy drinking
  • inactivity
  • obesity

• They found that men who had been active to begin with, as well as those who took up exercise during the study period, were at lower risk of experiencing impotence.

Exercise may ward off impotence for the same reasons it can prevent heart attacks, by keeping blood vessels clear.

In fact, impotence can be an early warning sign of coronary artery disease, since the penis is more sensitive to slow-downs in blood flow than the heart is, noted researchers.

Impotence affects about one quarter of American men by the age of 65, and there is no cure.

Urology August 2000;56:302-306.