A Boston doctor believes that excessive bicycling could lead to impotence

In this story:

• The seat is the problem
• 'It makes no sense'
• Related stories and sites

From Medical Correspondent Elizabeth Cohen

BOSTON (CNN) -- Bicycle riding may be excellent exercise, but a doctor in Boston says it can also be hazardous to a man's sex life.

In a study of 500 bike riders, Dr. Irwin Goldstein of the Boston University School of Medicine found that 4 percent complained that they were impotent. Among men in the study who didn't ride bicycles regularly, only 1 percent were impotent.

The men who rode more than 10 hours a week were the most likely to be impotent.

Goldstein also found that male and female cyclists have more difficulty achieving orgasms and urinating.

The problem, Goldstein says, is the seat. On most bicycles, the rider leans forward, compressing an artery that supplies blood to the penis.

"When you sit on a bicycle seat, you rest your 170-pound torso directly on the artery," says Goldstein.

Goldstein says that with frequent riding, the artery can become permanently compressed, which means no blood and no erection.

Goldstein presented his study this weekend at a meeting of urologists, some of whom said they thought there was a connection between bike riding and impotence.

While a 4 percent impotency rate isn't terribly high, Goldstein says he doesn't ride a bike and that other men should consider themselves warned.

"It absolutely makes no sense to take an organ of the human body and compress the arterial blood flow to it for any period of time," he says. "There is no logical way you could tell me that that's a good thing to do."

Fred Clements works for the bicycle industry, and he says he's never had a problem.

"Based on the people I deal with, who are bicycle shops around the country, it seems very rare if it happens at all," says Clements of the National Bicycle Dealers Association.

So should recreational bike riders worry?

"Certainly people need to realize that just jumping on an exercise bike 30 minutes a day is not generally going to cause this kind of damage," says Dr. Jenelle Foote, a urologist. "The people in this study were long-distance enthusiasts."

Goldstein says the solution is to change the way bicycle seats are designed so riders no longer lean on that all-important artery.