I'm a man and I'm engaged in a lot of sports and outdoor activities, but lately some of my friends said that biking could result in male infertility. Is this true? How? What are the other activities that could lead to male infertility? How can I stay healthy in terms of fertility?

While your friends may be right — biking has raised issues related to its effect on fertility in men — in most instances, cycling enhances good health. While men can be attentive to unusual sensations felt below the belt when biking, this doesn't necessarily mean that men are endangering their reproductive abilities. It means that men cyclists can lower their fertility due to the nature of the activity. Not to worry though — even in this state, most men still have enough motile sperm to reach and join with an ovum.

The average cyclist does not log enough miles to worry about fertility impairment. Furthermore, the cardiovascular perks of cycling outweigh incidents that interfere with sexual health and/or functioning.

Fertility often reflects your general health. If you are healthy and follow good healthy living, chances are your sperm will also be healthy. Avoiding obesity and stress are important in healthy fertility, and biking can be essential in steering clear of both of those things.

According to one study, men who experience grueling mountain-bicycling programs on rough terrains are apt to have lower sperm counts and more abnormalities of the scrotum than non-cyclists. The men in this study, however, spent more than two-hours-a-day, six-days-a-week riding mountain trails for 7 to 28 years, much more than even most avid cyclists would.

In this same study, mountain bikers had lower sperm counts than non-cyclists due to their higher scrotal temperatures during strenuous cycling. Higher scrotal temperatures destroy sperm. (This is why the testicles change position within the scrotal sack — because they need to maintain a constant body temp. As a result, when a man's body is hot from, for example, perspiration or fever, the testicles and scrotum naturally descend to allow the testes to cool. Similarly, when a man's body is cool, the testicles and the scrotum draw up close to his body to keep warm and raise their body temperature.) Being squashed between a man's body and a bicycle seat doesn't help. Traumatic compression also can occur when nerves both in the perineum (the area from underneath the testicles to the anus) and in the penile artery are pinched.

In addition, calcium deposits in the testicles can result from "repeated chronic microtraumatization" of the scrotum, causing scarring of blood vessels inside the testicles. Microtraumatization also causes sperm to be less mobile.

The lack of blood reaching the genitals after bike riding for hours can also affect erections. especially right after riding. Of course, erections usually resume after an hour or two (or three).

An October 2005 New York Times article stated that manufacturers of bike seats are now addressing the issue of traumatic compression for men. One newly designed seat, "The Eliminator," has a long groove extending down its center and is hollowed out in front. This design keeps the rider's weight off his perineum. Several other seat models with the same goal, such as specially designed flat seats (i.e., not shaped like a nose), are also now available for both street and mountain bikes. Bicycle shops may be knowledgeable about these and other new specialized seat designs.

Additional ways to prevent reproductive bike trauma include:

• Making the seat level, while pointing the nose of the seat downward a few degrees.
• Using a seat with gel padding.
• Checking to see that someone's legs do not fully extend at the bottom of the pedal stroke. Knees need to be slightly bent to support more weight.
• Sitting upright at a 90-degree angle, as opposed to leaning forward at a smaller angle.
• Spending less time on aero bars, handlebars that increase a rider's speed. The rider's position is changed to become more aerodynamic, therefore encouraging riding on the nose of the seat.
• Standing up every 10 minutes when riding to encourage blood flow through genitals.
• Lifting off of the seat when riding over railroad tracks, trail debris, or washboard terrain, using legs as shock absorbers.
• Watching for numbness while biking.

Depending upon your age and reproductive plans, you may want to see if you're fertile to begin with. If you are trying to conceive, staying away from excessive alcohol consumption and smoking can boost your fertility. Heavy drinking can lead to a decrease in sperm count and movement, and smoking harms sperm's motility. Recreational drugs, such as marijuana, cocaine, and anabolic steroids, can harm sperm health. Sperm develop over a three-month period; as a result, your mature sperm today may have been affected by how you lived three months ago.

If you experience continued pain when cycling or are simply concerned about your reproductive health, you can switch between using a recumbent bike (an exercise bike where you cycle as you sit without pressure being placed on the pelvis) and cycling outdoors. This balance will not only promote better reproductive well-being, but also allow you to experience the joys of riding outdoors.

It's important to be as informed as possible. As a result, you can take actions to protect your fertility. The following web site will give you further information on other activities that may place your reproductive health at risk, as well as some tips on staying healthy:

Men's Health — Male Factor Infertility on the University of Utah Health Sciences Center website

Alice

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