Men's health * Healthy living * Sexual health

Male elite cyclists risk infertility

high intensity training can affect sperm quality Intense training link to poor quality sperm

High intensity cycle training may lead to an increased risk of infertility, according to new research presented this week at the European Society of Human Reproduction and Embryology.

Scientists examined sperm samples from 15 healthy Spanish triathletes, average age 33, who competed at the national and international level. Athletes were asked to abstain from sex three days before giving samples.

They found that less than 10% of the sperm from all triathletes was normal-looking, and that cycling rather than swimming or running was responsible.

Men who cycled the most were found to have the worst quality sperm. Triathletes who cycled more than 300km (186 miles) per week, had only 4% normal-looking sperm. At this level, the men would face "significant fertility problems" said the scientists.

Professor Diana Vaamonde from the University of Cordoba Medical School in Spain commented: "It is something to do with the volume of training that they need to undertake to achieve and maintain a high level of fitness. We believe that the same effect would be observed in any athletes undertaking a similar amount of cycling training.”

Although the study design did not allow the scientists to pinpoint any single factor responsible for the reduction in sperm quality, they suggested that heat generated from wearing tight clothing, saddle friction and compression of the testes and cell damage caused as a result of the intense training may be contributory factors.

However men who like to cycle to work in the morning have little to fear.

Triathletes take part in some of the most demanding sporting events in the world. The "iron man" competitions require the athletes to swim 3.8km, cycle for 180km and then run a marathon!

Professor Vaamonde suggested that protective measures for elite sportsmen need to be considered such as developing training regimes to allow sperm to recover, or freezing athletes sperm before they begin such high intensity training.

She concluded: “We believe that we have uncovered a serious problem affecting triathletes who undertake significant amounts of training, and we hope that our research may lead to effective treatment.

This article was published on Tue 30 June 2009

Image © jazavac -

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