Cars Suck! -- Research


Get Off That Bike If You Value Your Penis

by Charlie McCorkell

The author is the proprietor of Bicycle Habitat, the favorite bike shop of this site's maintainer. Charlie delivered the following paper at a conference sponsored by the New York University School of Medicine in December, 2000. The conference discussed, inter alia, the supposed problem of cycling-induced impotence, which has been the making of several medical careers recently. The main offender is a Dr. Irwin Goldstein, who also spoke at this conference.


(Before I presented Dr. Goldstein did his customary attack on bike saddles, and Dr McCullough presented a power point show hitting the highlights of research to date and the health benefits of cycling.-- Charlie)

I'd like to thank Dr. McCullough for inviting me here today. I am both very appreciative and very nervous about this opportunity. I'm nervous because it's been a while since I addressed a large group, and, like most men, when the subject of "erectile dysfunction" (ED) comes up, all I want to do is put my knees together and put my hand in my pocket.

"Men should never ride bicycles. Riding should be banned and outlawed. It is the most irrational form of exercise I could ever bring to discussion." So says Dr Irwin Goldstein.

Over the years doctors have sent me many clients. They have come with stories of heart problems, diabetes, hypertension, mid-life weight gain, osteoporosis, and musculo-skeletal problems, all of which are addressable by a regular exercise routine. They have chosen bicycling because it is convenient, and fun. Over the years cycling has also sent many patients to doctors. Most went to emergency rooms or orthopedists. But when Bicycling magazine and 20/20 did their infamous pieces on cycling and ED, I thought I was probably sending some of my customers to urologists as well.

It wasn't until a month ago, when I got a chance to see the abstracts on the studies and some of the data, that I realized that what I had believed for the last 3 years might be wrong, and what I believed for the 20 years before that might be right: Cycling is good for your sex life.

The principal study citing a possible ED - cycling link is the Schwarzer study - AUA Abstract 952. This is adose-response survey study comparing the responses of cyclists and swimmers. The study found cyclists were twice as likely to suffer severe impotence than swimmers. Unfortunately, the report did not adjust the results for the fact the swimmers were on average 10 years younger than the cyclists, nor did the abstract detail the margin of error in the survey, which would push the impotency rates between the cyclists and swimmers into a statistical tie. In political terms, It's too close to call. The final blow to this survey came when a colleague of mine, Bud Hoffacker, the owner of Avocet cycling products, graphed the impotency rates of the cyclists against the findings of the Mass. Male Aging Study and demonstrated that when compared to the general male population, cyclists were half as likely to suffer severe impotence and 1/3 as likely to suffer any form of impotence. The conclusion he drew from the study is that cycling may not be as beneficial as swimming at mitigating or eliminating impotence. Also he concluded, at a minimum cycling does not expose riders to a higher risk of impotence.

The other major study was AUA abstract 941, titled "You don't have to ride in the Tour de France". This was a backwards study in which 1600 men with ED were surveyed and the 81 men self reporting that they believed bicycling was 50% responsible for their ED were studied. From this the authors concluded that "Bicycle riding associated impotence occurs in different forms of bicycle riding and riding exposures." In my shop a customer will come in with a flat tire, and he will often tell me why he got a flat. He will be wrong about the tire being punctured 2% of the time and wrong about the cause of the flat 50% of the time, I wonder if these same people can diagnose why they got a flat penis. What I would really like to see is some hard facts on cycling and ED.

The part of this survey which really jumped out at me was that 26% of the participants said they used aero handle bars. This is a system that moves your body into a more aerodynamic position by moving your center of gravity forward and down. This also has the effect of putting more weight on the perineal area. These riders, while making up 26% of the study group, make up about 1/10 of 1% of cyclists. This definitely suggests a risk area or a major flaw in the self identification of the study group.

Thankfully, for me, I'm moving off the topic of ED and onto safer ground: actual riding experience.

Over the last month I've spoken with a fairly large number of bicycle dealers, bicycle seat manufacturers and cyclists. Most of them wanted to make sure I told you about the health benefits of cycling, and how you as doctors should be shouting from the roof tops, or preferably from your bicycle seats, that everyone should be out riding bicycles because it's good for them, good for the environment and it's fun. I also heard over and over again denials about ED and stories from both riders and their partners about how cycling improves their sex life. One story from a couple on a multi day AIDS fund raiser got especially steamy.

When talking about cycling and ED it is important to keep in mind the Chinese experience. China has more people, more bicycles and more cyclists then any other country. Is this a coincidence? I remember seeing a news piece recently saying that the Chinese government was sending their top 20 cyclists to the US because they heard we were having erection problems in Florida.

One thing that came out over and over again is that most male cyclists who have logged any significant milage, 100 miles or more per week, have experienced genital numbness. This is usually referred to as "numb nuts" in the bicycle world. I have experienced it a half dozen times in my life. What constantly amazes cyclists is that for most of us, it disappears within an hour of getting off the bike and has no discernible effect on erectibility. (In New York, bike messengers and commuters don't seem to suffer from this condition much, I think because of the on-and-off riding style needed in New York traffic.)

The response among cyclists to genital numbness is generally to adjust their bike fit, change their saddle or change their riding style, and based upon my conversations this approach usually results in getting rid of future numbness. Better fit can be used to improve rider efficiency and eliminate many other cycling related aches and pains. Many bike shops have at least one person competent to adjust a bicycle well. There are also several fairly sophisticated bicycle fitting systems on the market. I've bought and used almost all of them with good success.

Good fit begins with the client. What kind of riding do they do, what kind of riding would they like to do, what special needs do they have, what kind of bicycle do they have. Before we can fit the rider to the bike we must know the rider and their bike.

The final position for the client can be anywhere from a road fit where 30% of the weight is on the pedals and 30% is on the hands and 40% is on the saddle to a relaxed beach fit with 10% of the weight on the hands, 30% on the pedals and 60% on the saddle.

Most fits start with leg length and adjusting the saddle height. There is a range of good saddle heights for any given rider. We usually start off by adjusting the saddle height to eliminate rocking of the hips when pedaling on a bike trainer. The saddle is generally set level to the ground or slightly downward. The foot is then positioned with the ball of the foot over the pedal spindle. The neutral seat position forward and aft is next found by dropping a plumb line from the bottom of the knee and positioning the seat so the plumb cuts through the pedal axle. Then the stem is fitted to give the rider the desired feel he wants. The main concession most cyclists make to genital numbness is to lower their saddle a little, removing weight from the seat, and tilting the saddle a little downward raising the perineal area off the saddle nose.

Some people have tried to resolve the issue of genital numbness by changing their equipment. Most of this activity is around saddle swaps, usually focusing on the new series of anatomically correct saddles. Dr Minkow of Specialized Minkow wedge fame has reported excellent anecdotal success with his saddle and SERFAS had their RX saddle tested by the UCSD sports medicine group. Their conclusion: "The Serfas prototype experimentally designed to limit central perineal pressure produced significantly less subjective and objective numbness compared to the standard seat in a one hour stationary cycling protocol. It appears that through bicycle seat design and innovation, perineal numbness can be decreased and more importantly may eliminate cycling associated perineal numbness and erectile dydfunction."

This report like some others have presupposed the truth of the unproven thesis relating bike saddles and impotency.

Padded bike shorts and padded bike underwear is also used to cushion and spread the contact area with the saddle, bike gloves are used to cushion the hands so more weight can be put on the hands and bike shoes are employed to keep the foot in the correct position and stop the heel from dropping, which may cause more weight to be transferred to the saddle.

The other important area touched upon by cyclists was how importantly riding style affects numbness. Shifting positions, occasionally rising out of the saddle, and so on can have a profound impact on genital numbness.

Now for the bad news: According to a study by the Sporting Goods Manufacturers, cycling participation has dropped from 53 million self identified regular cyclist in 1997 to 42 million in 2000. This is an unprecedented drop in participation. Some in the bike industry believe that Dr. Goldstein's remarks (and the mini industry he spawned) are at least partially responsible. The really bad news is that most of these lost cyclists have not replaced cycling with any other activity. Given the many health benefits of cycling a great many Americans may lead shorter, less healthy and less potent lives as a result of the incomplete research provided to date.

I encourage you all to encourage any patients you may see who are cyclists to try alternative bicycle fit if appropriate and I encourage all of you to encourage everyone you know to bicycle.

Every disease has a poster child. The bicycle industry has Lance Armstrong as its poster child on erectile dysfunction. Lance Armstrong has now won the Tour de France twice, but 4 years ago he was suffering intense pain in his testicles. After going to the doctor it was discovered he had testicular cancer and would need to have one removed the next morning. He was informed that because of subsequent chemo or X-ray treatment he might be rendered sterile. The doctor told him to go to the sperm bank and make a donation. Talk about pressure. You have one chance and one chance only to ever have children, and if he had to think about saddle induced erectile dysfunction I don't know what would have happened. Fortunately, aggressive chemo killed the cancer that had spread through his body, he twice won the Tour de France and his stored sperm have made him a father. Proving that a great cyclist can always rise to the occasion.

Thank you.


research index

Home