Straddling a commercially available narrow bicycle saddle resulted in absent or markedly diminished cavernosal artery peak systolic velocity values in all subjects while sitting on a commercially available two-cheek seat had no effect on cavernosal artery hemodynamics. Bicyclists who straddle on narrow saddles compress penile arterial inflow. It is hypothesized that chronic compression-induced endothelial damage may lead to focal penile arterial occlusion and permanent erectile dysfunction.

Affidavits of this study are available on request.

Riding Rough: New Evidence Continues to Link Biking to Impotence by Jim Thornton

FACT: In a recent study published in the journal Radiology, 94% of males who engaged in “extensive off-road biking” showed scrotal abnormalities – compared to 16% of nonbikers.

In 1997, Boston University impotence researcher Irwin Goldstein terrified macho cyclists everywhere with his claim that road biking had caused at least 100,000 cases of permanent impotence in American men. Though at the time many urologists suggested that scientific studies in support of Goldstein’s charge were, well, soft, new research indicates that cyclists’ overall sexual prognosis may be more disturbing than previously thought.

The gist of the original argument: When a rider straddles a bike seat, he or she is not resting on the “sit” bones that we bipeds evolved to safely cushion our body weight; instead, the weight is distributed on the base of the genital tracts, through which course the nerves and arteries that supply the penis and the clitoris. “Why would any rational human being want to put a 150-pound weight on these structures?” asks Goldstein. Over time, he maintains, chronic pressure can trigger everything from numbness and shooting pains to reduced blood flow and localized hardening of the genital arteries – leading to erectile dysfunction in men and inability to reach orgasm in women.

Two recent papers bolster such allegations. In the first, researchers analyzed data from the Massachusetts Male Aging Study, which has been following 1,709 men ages 40 to 70. Men who rode a mere three hours per week had a 72% higher risk of impotence than nonbikers. The second study – in response to California bike cops’ complaints of genital numbness – found a direct inverse correlation between the duration of nocturnal erections and the number of hours spent on duty.

Now comes a new worry, at least for diehard male mountain bikers. According to Ferdinand Frauscher, a urological radiologist in Innsbruck, Austria, the sport’s legendary jolts could put fertility at risk as well. “Repetitive shocks and vibrations, “ he says, “may be damaging blood vessels in the testicles, which decreases blood flow and may result in changes in sperm and semen quality.”

These studies are relatively small, but even if data proved the anti-bike case, says Sam Callan of USA Cycling, a bicycling governing body, elite riders will ignore it. “The guys racing at the top level have an invincible attitude,” he says. “Even if they knew for sure that one out of three of them would become impotent or infertile, they’d think, it won’t happen to me.” For everyone else, experts suggest these steps:

Get a bike that fits. “When your leg is at drop dead bottom,” says Callan, “you should still have a little bend at your knee.” And a full suspension ride may reduce impact almost fivefold.

Don’t stay wedded to the saddle. Take periodic breaks and stand up frequently to relieve pressure (ditto for stationary bikers).

Pick the right seat. Though cut-out seats have been shown to reduce numbness, Goldstein calls their health benefits a “fantasy.” Your safest bet: a noseless two-cheeker like the Easyseat.

"Impotence and Nerve Entrapment in
Long Distance Amateur Cyclist."
Andersen K.V., Bovim G.
Laboratory of Clinical Neurophysiology,
Trondheim University Hostpital, Norway.

"Does Bicycling Contribute
to the Risk of Erectile Dysfunction?"
Goldstein I., Marceau L., Kleinman K., McKinlay J.