Cyclists should be more worried about their sexual health than that pothole during your morning commute. For men, cycling won’t affect you physical but may affect you hormonally.

Riding your bike as part of your commute, on the weekends or on the occasional long ride is fine and promotes healthy living. That kind of exercise can improve quality of life, reduce body fat and improve the cardiovascular system. For serious cyclists, and in particular endurance athletes, extensive cycling may affect the levels of reproductive hormones in the body.

Cyclists that may be at risk include serious leisure cyclists and cyclists who compete in races or ride for extreme endurance. The study was led by Leah FitzGerald, PhD, from the University of California at Los Angeles’ School of Nursing and involved 107 male athletes between the ages of 18 to 60. The men were placed into three groups, 16 men were triathletes, 46 were cyclists and 45 were recreational athletes.

The researchers took blood samples to measure for testosterone, cortisol, estradiol and interleukin-6 in addition to other hormones. The men also answered a questionnaire that provided an estimate of the levels of physical activity during the week and inactivity during the week.

Cortisol helps in fat metabolism and increases blood sugar levels. Interluken-6 is a protein that is a part of the body’s immune system response to inflammation and plays a role in diseases like prostate cancer, rheumatoid arthritis and diabetes.

The hormone that most men should be concerned about is estradiol, which is a form of estrogen. Estradiol is produced by men as part of the breakdown of testosterone. Elevated levels of estradiol can lead to enlarged breast tissue or pubic hair loss.

In the study, levels of estradiol and testosterone were significantly higher in serious leisure cyclists than the two other groups. Estradiol levels were over two times higher for cyclists than the triathletes or recreational athletes. These early results warrant further study to determine how cycling may be associated with increasing the risk of sexual reproductive problems.

Researchers also noted the use of chamois cream for cyclists. Nearly half, 48.5 percent, of cyclists and 10 percent of the triathletes used chamois cream that contains paraben. Chamois creams help prevent chaffing and possible infections from saddle sores and contains lubricants, oils as well as paraben, which is used as a preservative and helps prevent bacterial growth.

While no links were made, paraben is a weak estrogen mimic. Researchers noticed an association between estrogen levels and the number of years of chamois cream use. Future studies could help determine if there is any cause and effect or any associated increased risk in regards to chamois cream use.

For cyclists, science has not been kind. Just recently, a new study highlighted the impact cycling has on female sexual health, including genitalia numbness.

The study was published in the European Journal of Applied Physiology.