Moderate exercise may help boost sexual function in men with heart failure, according to a new study from Italy.

The results may be good news for some men with erectile dysfunction, because Viagra and other similar impotence drugs can have dangerous interactions with medications commonly prescribed to treat heart failure.

"If confirmed in larger trials, these results may suggest a potential role for exercise training as a non-pharmacological therapeutic strategy to improve sexual dysfunction in men with chronic heart failure," Dr. Romualdo Belardinelli and colleagues at the Lancisi Heart in Ancona, Italy, report in the May 11th issue of the International Journal of Cardiology.

In chronic heart failure, the heart becomes enlarged and loses its ability to pump blood efficiently. Symptoms include breathlessness, fatigue and swelling of the feet due to fluid accumulation.

Although the condition may be caused by a number of factors, poor blood vessel function is believed to play a role in many cases. Similarly, improper functioning of the endothelium -- the lining of the blood vessels -- is often involved in erectile dysfunction.

Research has shown that exercise can improve blood-vessel function, so Belardinelli's team set out to see whether moderate physical activity could improve symptoms of heart failure and boost sexual function.

The study included 59 men with chronic heart failure, which had been stable for at least 3 months.

Half of the men were randomly assigned to participate in a supervised exercise program while the other half did not exercise during the 8-week study. The exercise program included riding on a stationary bicycle and stretching three times a week.

At the end of the study, men who did not exercise did not experience any improvement in heart failure symptoms or sexual function.

In contrast, men who participated in the exercise program experienced an increase in oxygen uptake during exercise. They also experienced improvement in several measures of sexual function, including the quality of their erections. The improvement in sexual function was accompanied by an improvement in men's relationship with their partner, the study found.

"This is the first demonstration that short-term moderate intensity aerobic exercise training improves sexual activity in men with stable chronic heart failure," Belardinelli and his colleagues conclude. They suspect that improvement in sexual health is most likely due to exercise-related improvement in blood-vessel function.

The researchers caution that the findings of the small study need to be confirmed. But they note that exercise may turn out to be an effective alternative for men with erectile dysfunction who take nitrate drugs to treat heart failure. Men who take nitrates may experience a dangerous drop in blood pressure after taking Viagra and other similar impotence drugs