June 29, 2009

Excessive Cycling Leads To Low Sperm Count

Men who spend more time riding a bicycle are increasing their chances of damaging their sperm, according to new research.

Previous studies have found a link between cycling and low sperm quality.

The recent study showed that triathletes who rode more than 186 miles each week had less than 4 percent normal looking sperm.

Professor Diana Vaamonde, from the University of Cordoba Medical School, Cordoba, Spain, presented the new findings at the annual conference of the European Society of Human Reproduction and Embryology on Monday.

Researchers compared the activities of running, swimming and cycling in 15 Spanish triathletes to determine how each of them impacted sperm quality. They noted a clear link between time spent riding a bike and the overall quality of sperm.

"While all triathletes had less than 10 percent of normal-looking sperm, the men with less than four percent -- at which percentage they would generally be considered to have significant fertility problems -- were systematically covering over 300 kilometers (180 miles) per week on their bicycles," Vaamonde said.

She said that although the study's design doesn't provide reasons for the problem, she believes that it could be due to irritation and compression caused by friction of the testes against the saddle, or the localized heat produced by wearing tight clothing.

"The fact that this effect is greater in triathletes than in other sports practices seems to indicate that it is something to do with the volume of training that they need to undertake to achieve and maintain a high level of fitness," said Vaamonde.

"We are now beginning chromosomal analysis," she said, "in the hope that a better understanding of the biological mechanisms underlying this problem will lead us towards developing protective measures for these sportsmen."

"We believe that all the factors inherent in this sports activity, especially with regards to the cycling part, may affect sperm quality; moreover, we think that normal physiological homeostasis "“ the body's ability to regulate its own environment "“ may become irreversibly altered, therefore resulting in complex anomalies," she said.


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