High levels of cycling training damage triathletes' sperm

June 29, 2009

Amsterdam, The Netherlands: The high-intensity training undertaken by triathletes has a significant impact on the quality of their sperm, the 25th annual conference of the European Society of Human Reproduction and Embryology heard today (Monday 29 June). Professor Diana Vaamonde, from the University of Cordoba Medical School, Cordoba, Spain, said that the triathletes who did the most cycling training had the worst sperm morphology.

Professor Vaamonde's team has previously shown that both high exercise intensity and high exercise volume may be detrimental to sperm quality. They decided to take a more profound look at the sportsmen who seemed to show the greatest alteration - the triathletes - and assess the correlation between the volume of training in each activity and sperm quality. Of the three modalities, only cycling, the activity for which triathletes undertake the most training, showed a clear correlation with sperm quality. The more cycling training the sportsmen undertook, both in time and kilometres, the worse their sperm quality became.

The design of this particular study did not allow the scientists to isolate a single factor responsible for this problem, but Dr. Vaamonde believes that it is likely to be mainly due to either the irritation and compression caused by friction of the testes against the saddle, or the localised heat produced by wearing tight clothing. However, she also believes that reactive oxygen species - small molecules that are a natural by-product of oxygen metabolism and which react to stress by increasing to such an extent that they can damage cell structures - and energetic imbalances may play an important role in the alterations in sperm that the team observed.

"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 Professor Vaamonde. "We believe that the same effect would be observed in any athletes undertaking a similar amount of cycling training."

The team studied the semen values of 15 healthy Spanish triathletes, with an average age of 33. They were competing at both national and international level. Their training routines were analysed in detail, and particular note taken of the time they spent cycling each week. Sperm was taken after three days of sexual abstinence and analysed for their shape and form.

"We found a statistically adverse correlation between sperm morphology and the volume of cycling training undertaken per week," said Professor Vaamonde. "While all triathletes had less than 10% of normal-looking sperm, the men with less than 4% - at which percentage they would generally be considered to have significant fertility problems - were systematically covering over 300km per week on their bicycles."

Up to now, Dr. Vaamonde and her team have only undertaken observational analysis of the triathletes' sperm. "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.

Triathletes undertake what is possibly the most demanding sporting activity in the world, with the most punishing 'iron man' competitions involving 3800 metres swimming, 180 kilometres cycling, and running a marathon (just over 42 kilometres). Recent research has shown that the risk of dying from a heart attack in a triathlon is nearly double that of dying in a marathon alone. Dr. Vaamonde's findings add another layer to this health problem.

The scientists believe that the changes they observed may have to do with energetic imbalances, which they will assess in the future. They also intend to observe semen anomalies at different training points in order to better understand the physiopathological processes.

"Protective measures for these sportsmen need to be developed. Depending on the mechanism leading to the creation of abnormal sperm, these could include giving antioxidants and modifying training regimes to allow for recovery. Or we could take preventive measures by freezing athletes' sperm before they start high intensity training," said Professor Vaamonde. "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."
-end-


European Society of Human Reproduction and Embryology

Related Sperm Articles from Brightsurf:

Nut consumption causes changes in sperm DNA function
Researchers have evaluated for the first time the effect of a short/middle-term consumption of a mixture of tree nuts (almonds, hazelnuts and walnuts) on sperm DNA methylation patterns in healthy individuals reporting eating a Western-style diet.

Collecting sperm from Covid-19 patients
How does Covid-19 affect sperm and thus the next generation´s immune system?

Paleontology -- The oldest known sperm cells
An international team of paleontologists has discovered giant sperm cells in a 100-million year-old female ostracod preserved in a sample of amber.

Research captures how human sperm swim in 3D
Using state-of-the-art 3D microscopy and mathematics, Dr Hermes Gadêlha from the University of Bristol, Dr Gabriel Corkidi and Dr Alberto Darszon from the Universidad Nacional Autonoma de Mexico, have reconstructed the movement of the sperm tail in 3D with high-precision.

Overweight and obesity are associated with a low sperm quality
Researchers from the Rovira i Virgili University in collaboration with researchers from the University of Utah have carried out a systematic review and meta-analysis evaluating the association between adiposity (normal weight, overweight, obesity, and low weight) and the sperm quality.

Diet has rapid effects on sperm quality
Sperm are influenced by diet, and the effects arise rapidly.

Sperm may offer the uterus a 'secret handshake'
Why does it take 200 million sperm to fertilize a single egg?

Long duration of sperm freezing makes no difference to live birth rates in large sperm bank study
Despite a time limit imposed in many countries on the freeze-storage of sperm, a new study from China has found that the long-term cryopreservation of semen in a sperm bank does not affect future clinical outcomes.

An important function of non-nucleated sperm
Some animals form characteristic infertile spermatozoa called parasperm, which differ in size and shape compared to fertile sperm produced by single males.

DNA of sperm taken from testicles of infertile men 'as good as sperm from fertile men'
Scientists have found that sperm DNA from the testicles of many infertile men is as good as that of ejaculated sperm of fertile men.

Read More: Sperm News and Sperm Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.