Photo of a man bicycling across courtyard.

Photo by g-stockstudio, Shutterstock.

Stanford Medicine Scope - March 2nd, 2017 - by Jennifer Huber

When I think about bicycle safety, I think of lights, helmets and strategies to share the road with cars.

But physicians have a different perspective — too many hours on a bicycle saddle can compress vital arteries and nerves to cause numbness, pain and sexual dysfunction. This risk is likely affected by the design of the saddle, fit of the bike, riding position, ride duration and a host of other factors.

But there’s a lot that remains unknown. So Michael Eisenberg, MD, an assistant professor of urology at Stanford, is conducting the Stanford CYCling and Lower Effects (CYCLE) study to hone in on the factors affecting the comfort and safety of cycling. He’s collaborating with Roger Minkow, MD, a Bay Area-based saddle designer and ergonomic consultant.

The researchers are inviting volunteers to answer a brief online survey about their bicycling habits, equipment and health. I recently reached out to Eisenberg to learn more.

What inspired you to conduct the CYCLE study?

About 20 years ago, several studies demonstrated an association between cycling, erectile dysfunction and even infertility. Many of these health issues can be reversed if caught early, but they can become permanent over time. Since then, the bicycle industry has undergone a major redesign of equipment to try to mitigate the risk. And it’s been years since a large study has been conducted to understand the current prevalence of sexual dysfunction in riders and to understand if there are cycling related factors — such as duration of riding and saddle design — that are contributing.

Cycling is quite popular in this area, and I have several patients who have come in over the years complaining of genital pain, numbness or performance issues. Recently, the saddle designer Roger Minkow reached out to me about the topic. We created and initiated the CYCLE study in October 2016 to help understand the current state of cycling on pelvic and sexual health for male and female riders. We’re very excited about the study and hope it will help make the sport safer and more comfortable.

How can cyclists participate?

Cyclists participate in the study by completing a brief online survey that takes about 15 minutes. In the survey, we obtain a comprehensive look at the cycling habits of men and women, including the type of riding they do, their intensity level and details about their equipment. We then ask participants about their overall health — such as their weight, body measurements and basic medical history. Finally, we ask validated questions related to sexual function and how it corresponds to their riding habits.

Nearly 1,500 people have participated in the study so far. There are so many different types of cyclists and equipment in common use. In order for us to effectively compare these, we need about 8,500 more participants.

Can you give an example of how you treat a cycling-related health problem?

I recently saw a man with persistent penile numbness after several long bike rides. We reviewed risk factors and pelvic anatomy related to his condition. We then discussed certain cycle practices he can modify to allow him to be able to cycle as much as he’d like without the symptoms, and these modified practices have worked well.

In generally, cyclists really love to ride so my goal is not to tell them to stop. I look at a patient’s equipment, body position, saddle design, riding habits and when symptoms occur — to come up with a personalized strategy for that rider. In select cases, I even prescribe some medications to help circulation.

Do you cycle?

Yes, I cycle on the road for both pleasure and exercise. We live in a beautiful area. One of my favorite rides is around my neighborhood along Foothill Expressway and Junipero Serra Boulevard.

Originally published at Stanford Medicine Scope Blog