Lower sperm quality found in active cyclists

Researchers in Spain have recently found that active male cyclists can have infertility risks due to lower sperm quality.

A team led by professor Diana Vaamonde, from the University of Cordoba Medical School, tracked the workout regimen of 15 Spanish triathletes, with an average age of 33 who had been training for at least eight years, while also monitoring their sperm morphology.

For those in the test group that covered more than 180 miles per week on their bikes, the percentage of normal looking sperm dropped from a group average of 10 percent to 4 percent, a rate where infertility problems begin. Increased swimming or running did not affect sperm quality.

"We found a statistically adverse correlation between sperm morphology and the volume of cycling training undertaken per week," Vaamonde said. "We believe that all the factors inherent in this sports activity, especially with regards to the cycling part, may affect sperm quality," she added. "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."

This study was a follow up on research released in 2002 that had similar results for mountain bikers. 40 men who biked two hours a day were compared to 30 non bikers. The results showed that the bikers had only half the amount of sperm than the non-bikers.

"The exact causes for the decreased sperm motility are unclear. We believe that repeated mechanical trauma to the testicles results in some degree of vascular damage, and may thereby cause a reduction in sperm motility."

Vaamonde noted that the possible reasons for this could be due to the increased heat during exercise, pressure and repeated friction against the seat causing microtrauma on the testes, and the overall rigor of intense exercise. They say that for casual bicyclists the risk is much lower.

Source