Cycling Doesn't Cause Male Infertility: Study
Keith Barnard, MD
July 9, 2014 -- Cycling doesn't lead to male infertility and erectile dysfunction, but it may raise prostate cancer risk in cyclists over 50, a new study finds.
Although it's considered a healthy activity, helping to lower the risks of type 2 diabetes, heart disease, and stroke, cycling is commonly believed to affect a man's fertility.
Researchers from University College London looked at data from 5,282 male cyclists who took part in the Cycling for Health U.K. Study.
Men were recruited through cycling magazines to do an online survey. They reported whether they had erectile dysfunction, whether they'd been diagnosed with infertility, or had prostate cancer.
Weekly cycling time was grouped into: below 3.75 hours, 3.76-5.75 hours, 5.76-8.5 hours, and over 8.5.
There was no link between infertility or erectile dysfunction and many miles of cycling a week, even for more than 8-and-a-half hours.
Study author Mark Hamer, PhD, says today's saddle technology may be helping ”to relieve pressure on nerves to prevent the uncomfortable ‘numbness’ sensation that can occur when riding for a long time."
Cycling and Prostate Cancer
Cycling is linked to raised levels of the protein PSA, or prostate specific antigen, which can be a sign of prostate cancer. This is because pressure from the saddle can massage or mildly injure the prostate in a minor way and cause inflammation, driving up the PSA level. An avid cyclist may end up getting unnecessary testing if a mildly raised PSA level is found that's due to cycling and not cancer.
But this is complicated by the fact that this study suggests a much-increased cycling time of more than 8.5 hours a week is tied to a higher risk of having prostate cancer.
Hamer says the results should be interpreted cautiously, and there may not be a direct cause and effect: "For example, it may be the case that these men are more aware of their health and visit the doctor more, thus more likely to get such conditions picked up."
He says more research is needed, adding that the risk was high only in the most avid cyclists: "Moderate levels of cycling are associated with many other favorable health benefits, so any risks are likely outweighed by the benefits."