Bicycling And Prostate Problems

Done improperly, even casual cycling can cause problems ranging from temporary penile numbness to infertility.

Now hold on. Before all the color drains from your face, keep in mind that simple precautions prevent many of these problems, and most others are easily resolved. Cycling and sex aren’t oil and water. In fact, scientists (and many happy cyclists) believe that spinning your wheels can improve your sex drive.

Bicycling can be hard on your prostate.

Bicycling can be hard on your prostate.

Before we celebrate this fact–and you can be sure we will–let’s look at 6 of the most common cycling-related problems in the male reproductive system.


To understand this, and most of the other problems we’ll discuss, you must understand the prostate. This walnut-shaped gland has a few purposes.

The prostate has muscles that contract to help squirt 2-4 milliliters of semen (containing 100-600 million sperm) out of the penis during ejaculation. It also helps the sperm swim and keeps them safe by producing lubricating fluids that neutralize vaginal acidity. This secretion and others produced by various organs contain sugars and nutrients for the sperm. They comprise most of the volume of semen (less than 10% is sperm).

The gland lies between the scrotum and anus–the area that has most contact with the saddle. “The prostate is just a finger’s width away when you sit on a bike seat,” says H.R. Safford III, M.D., a Denver urologist.

Constant proximity to the saddle can “bruise” the prostate, says Wayman Spence, a Waco, Texas, M.D. who did just that 8 years ago in the Spenco 500 ride. When this happens, the prostate swells and puts pressure on the nearby perineal, dorsal and pudendal nerves, which feed into the penis. Numbness occurs.

If you stay off the bike, the condition usually disappears within a week with no aftereffects “other than a mild loss of enthusiasm before the next ride,” says Jeffrey York, an M.D. in the division of urology at Ohio State University.

The simplest way to avoid this situation is to stand on the pedals more while riding, or shift your weight around on the saddle. Doing this at least every 30 minutes should minimize the pressure that inflames the prostate. If this doesn’t work, try one of the remedies in the “Quick Fixes” sidebar on page 59.

Also beware of the forward position fostered by an aero bar. If you’re just beginning to use such a model, ease into it. Ride 15-25 minutes (or less) in the aero position, then the same amount in your normal posture before switching back. Even experienced aero bar riders should sit up at least once every hour.


Cyclists who traumatize their prostate might also suffer from urine flow that is frequent, infrequent, bloody, terminally dribbling, or which causes a burning sensation (thankfully not all at once, though).

These symptoms usually arise when the prostate is irritated beyond bruising to full-blown infection, or prostatitis. The infection interferes with the prostate’s ability to monitor the reproductive system’s fluid output, and strange things begin happening. The cure is simple: antibiotics and time off the bike. Two weeks of each is usually enough.

Bloody urine also occurs in endurance events. The kidneys can bleed because they “just work too hard” reabsorbing water, filtering blood, and excreting waste, explains Spence.

And during jarring activities such as mountain biking, the walls of an empty bladder can bump against each other and bleed, says York. (One more reason to stay well hydrated.) Also make sure that when you catch big-time air you don’t catch big-time saddle. In ’86, the New England Journal of Medicine reported a case of “Huffy-Bike Hematuria.” A 13-year-old cyclist had bloody urine because during his BMX jumps he’d bang against the seat, harming his prostate.

Scary as these problems appear, they’re usually harmless displays–smoke bombs as opposed to hand grenades–created by the body to get your attention and warn you to stop an activity that could lead to permanent damage. But these symptoms can also be caused by ailments (such as kidney infection or bladder cancer) that are far more dangerous, even life-threatening. For this reason, it’s best to assume that urinary problems aren’t caused by cycling. See a doctor. If the diagnosis blames your bike, be glad. The only immediate danger is that you’ll get bored because you can’t ride.

If your forced vacation from cycling begins to seem unbearable, just think about how riders used to solve this problem.

Prostate “massage” was one of the primary jobs of pre-World War I urologists. Some folks thought a neglected prostate harbored “bad humors” that built up and contributed to (besides urinary difficulties and numbness) arthritis and even epilepsy. We recognize this as quackery now, yet medical journals of that era advertised self-massaging machines. These devices were similar to stationary bicycles, only with a 4-inch “dildo” on which a person would sit, says York. Pedaling caused the device to massage the prostate through the rectum wall.



BICYCLING occassionally receives letters from guys who, in roundabout and somewhat tentative language, ask if our medical experts know of any condition that might cause male cyclists to ejaculate while riding.

Is there such a condition, or do these guys love cycling more than the rest of us?

York says that the motion of the legs and hips during pedaling can sometimes create an indirect form of prostatic massage. When this happens, the gland is “milked” and emits fluid. It’s not ejaculation (no sperm is delivered from the testicles), just a sticky discharge of the prostate’s lubricating liquid.

The remedy for this leaking, says Safford, is to reduce the fluid pressure inside the prostate with more “masturbation or intercourse.” Tough medicine.


Most males are surprised yet grateful the testicles don’t get traumatized more often in cycling.

Each of these complex organs comprises 275 yards of delicate coiled tubes that make sperm. These seminiferous tubules lead to the epididymis, a 20-foot coiled structure behind each testicle in which sperm mature. The spermatic cord ascends from this coil to the urethra (the tube running from the bladder), through the prostate, and out the penis. The cord contains blood vessels and the vas deferens, the tube that transports sperm (and the one that’s cut in a vasectomy).

Despite the fact that cycling buffets these free-hanging and sensitive organs between pumping thighs, and bounces them on the bike seat, they aren’t harmed. Credit some of this safe passage to bicycle shorts. Like jock straps, they provide some protection by compacting and containing the package.

But in a crash, this same tightness can work against us. Because the scrotum can’t swing freely on impact, it might be more susceptible to injury.

York had a patient whose problem was predictable and mercifully rare. During a crash, one testicle became trapped between saddle and bone. The testicle ruptured, and part of it had to be removed.

No doubt this hurt as much as we imagine it did, but even here the news is relatively good. Losing one testicle in a wreck won’t make you infertile. The other can often supply enough sperm to compensate.


Accidents can damage the reproductive system in other ways. Because the penis extends from the body, it can be hurt during a crash.

York has treated 2 cyclists who fell on their handlebars and damaged the blood vessels in the penis, resulting in the ability to have only a partial erection. An erection happens when these vessels fill with blood and widen. It is maintained by muscles that contract and trap the blood.

In York’s patients, blood entered the vessels but leaked through the damaged artery wall into adjacent veins and back out the penis. This caused partial limpness. After York blocked the damaged artery, the remaining ones worked fine to produce an erection.


This is the big one, the grandaddy of all fears: Can cycling sap your sexual prowess?

Yes, especially if you consider the broadest definition of impotency, which is the “inability to maintain an erection that’s mutually satisfactory for both partners,” says York. In a heterosexual relationship, this wide-ranging term can be applied any time the man either doesn’t get it up or keep it up long enough for intercourse. So technically, any of the problems we’ve discussed could lead to impotency.

This condition affects most men sometime in their lives, says York, but cycling is one of the least-common causes. It’s usually psychological in origin (from stress, anxiety, guilt, depression), or caused by such physical complications as diabetes, alcoholism, or certain medications. Impotency is treatable and almost always temporary.

Infertility is different. It refers to the inability to conceive (15% of couples of childbearing age are infertile). Among the many things that can contribute to male infertility are infections, injuries, a general failure to produce enough sperm, and, yes, cycling.

Evidence is sketchy, but scientists know that under certain conditions cycling, like other endurance sports, can reduce testosterone levels.

Testosterone, a hormone produced in cells between the seminiferous tubules, is responsible for sperm development and male characteristics such as growth of sex organs, distribution of body hair (including baldness), lowering the voice, and muscle growth.

In a study in the August ’91 Medicine and Science in Sports and Exercise, Ruddy Dressendorfer, Ph.D., measured testosterone in marathoners who doubled their regular mileage during 15 days of racing. The levels fell 31%. This is consistent with older research involving cyclists, rowers, runners, and swimmers that showed a 20-30% drop in testosterone after intense and prolonged (more that 2 hours) exercise.

Scientists are also beginning to suspect that, aside from sudden training increases, long-term participation in sports such as cycling might also lower testosterone.

In a study to be published this year in Fertility and Sterility, Mary Jane De Souza, Ph.D., checked sperm quality and testosterone in established runners (60-plus miles a week), weight trainers (2-plus hours, 4-plus days a week), and a control group of average men.

In both exercise groups testosterone levels were about 25% lower than the controls. In the runners, sperm count, motility and its ability to penetrate the cervical mucus were lower, and there were more immature sperm cells.

Why such differences? “We don’t know,” says De Souza, who works at the University of Connecticut Health Center. The jarring that occurs during exercise may negatively affect testicle cells. Others theorize that anxiety and stress may influence the part of the brain that regulates the production of testosterone.

One extra problem for cyclists may be that our testicles are hampered inside hot shorts. Testicles need a cool environment to thrive. This is why males have scrotums–to keep testicles cooler than the inner body temperature.

In a follow-up study, Dressendorfer devised what he calls an “antifreeze diaper,” a nylon liner containing a coolant. It keeps things cool throughout an hour of exercise. But even with this twist, testosterone levels still dropped, he says.

Despite the undeniable dive in this important hormone, it’s important to remember that no clear-cut evidence links moderate cycling to infertility.

Also keep in mind that the decreases caused by increased riding seem to be temporary. Testosterone levels return to normal with a week of rest or reduced training. Anyway, the drop-off may not matter. Even with lower testosterone levels, most cyclists are still fertile. Only men whose sperm count is normally low face possible infertility from a further drop.

“It’s important not to send an alarming message,” says Dressendorfer, director of the exercise science laboratory at New Mexico Highlands University. “You can do very heavy training and still be fertile.”


And relax. After all the dire warnings, it’s time for perspective.

Although no definite numbers are available, researchers and doctors estimate that only a small percentage of male cyclists ride long or hard enough to paralyze their penises, become impotent, or suffer any of the other horrors we’ve discussed.

And even the few studies issuing warnings to the hammerheads seem to be inconclusive and outweighed by anecdotal evidence indicating the opposite effect. The Dutch study, for instance, was quickly disputed by pro cycling’s medical commissions and racers. (In one of the more acid comments, Franceso Moser, world hour-record holder, told the Italian La Gazzetta dello Sport that, “I would like to meet the wives of these two doctors.”)

The best news is that moderate cycling can improve your sex drive. Loren Cordain, a Ph.D. in the department of exercise and sports science at Colorado State University, says, “There is no doubt that when a sedentary person takes up moderate exercise, libido is enhanced.”

Compared with sedentary sorts, exercisers usually have better circulation, sleep, diets and flexibility, and can elevate their endorphins (one of the hormones that make us feel pleasure) to higher levels. These are pluses for sexual pleasure. Exercisers also tend to have less fat. York says fat contributes to the production of estrogen (a feminizing hormone). A high level can depress sex drives in men by countering the masculinizing effects of testosterone.

Perhaps the biggest benefit of exercise on libido is to the mind. In his book, The Exercise Habit (Leisure Press, Champaign, IL; $13.95), James Gavin, Ph.D., cites surveys that found that people are more aroused after exercise, wanted (and got) more sex the more they exercised, and maintained sexual activity longer into old age.

A big reason is that “exercise gets you to live in your body, not just on top of it with your mind,” says Gavin, a sports psychologist at Concordia University in Montreal. “Hundreds of studies show that exercise improves self-esteem,” which improves sex. In plainer words, he says, “If you feel like shit, you don’t feel sexy.”

So ride with confidence. Cycling helps not only your head and overall health, but also your sex life. Just remember to respect your reproductive system. Take care of it, and when the time comes it will take care of you.

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