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Another Risk for Bike Riders?

By Paul Feinberg '85

Published Jun 8, 2012 1:54 PM

Is cycling bad for making babies? Possibly, according to a new study conducted by the UCLA School of Nursing.


Serious cyclists face a lot of risks. On city streets, there are cars to dodge and pedestrians to avoid. Off-road, one missed divot can send you head over handlebars. But the study also found that "serious leisure male cyclists may experience hormonal imbalances that could affect their reproductive health." UCLA Assistant Professor Leah Fitzgerald, the principal investigator and lead author of the study, describes a serious leisure athlete as someone who cycles at least eight and as many as 15 hours a week.

The study looked at the relationship between exercise intensity and circulating levels of reproductive hormones in serious cyclists, triathletes and recreational athletes. Fitzgerald was drawn to the subject by the results of an earlier study in which she found low bone density in serious cyclists as young as 40, an atypical condition in men that young. Wondering why, she and her co-authors (including UCLA Nursing School Professor Wendie A. Robbins) decided to check reproductive hormones.

The researchers also looked at whether the test subjects used paraben chafing creams, which usually contain estrogen, and while the study did not reveal a direct correlation, the affect of the cream was worth noting in the report.

"We're not trying to say that cycling is bad, and this was just a small cohort. We just need to investigate this a little further," she says. "We need a larger sample of cyclists, more triathletes and a control group. If there is some information we can feed back to that population, that would be great, but right now we're just in the learning process."