Preliminary study suggests frequent cycling could affect male fertility

December 13, 2010 by Lin Edwards report

(PhysOrg.com) -- A study of men attending fertility clinics has found bicycling for five or more hours a week was associated with low sperm count and poor sperm motility.

Previous studies of competitive cyclists has linked the sport to poor as well as urinary and genital problems, but until now no such links have been shown in non-competitive cyclists.

Dr. Lauren Wise, Associate Professor of Epidemiology at Boston University School of Public Health (BUSPH), decided to see if there was a relationship between and fertility. Along with her colleagues she studied 2,261 who were members of couples attending one of three fertility clinics in the Boston area between 1993 and 2003. She gave each of the men about to undergo their first IVF cycles a questionnaire that included questions about their exercise levels, type of exercise, general health and medical history, and each man also provided at least one semen sample.

The results of the prospective cohort study, published in the journal showed that, after adjustment for variables such as multivitamin use, blood pressure, weight, and type of underwear worn, exercise levels generally had no overall impact on sperm quality and quantity.

When the researchers broke the data down into specific forms of exercise, they found that men who bicycled for five hours or more a week were more likely to have a low sperm count and poor quality (low motility) sperm than men who did not exercise at all or those doing other forms of exercise. Less than a quarter of the non-exercisers had a low sperm count compared to 31 percent of the frequent bike riders. Just over a quarter (27 percent) of the sedentary men had poor sperm motility compared with 40 percent of the cyclists.

Dr. Wise speculated that semen may be affected by temperature increases in the scrotum or trauma while cycling, but said it was much too early to be sure of the cause, and she added that it is as yet “unknown whether itself actually caused the issues with their .” Since the men were attending fertility clinics, it is also not possible to say whether or not the findings would be the same among the general population, and further research would be needed to make any firm conclusions.

More information: Physical activity and semen quality among men attending an infertility clinic, Fertility and Sterility, doi:10.1016/j.fertnstert.2010.11.006

Related Stories

Recommended for you

Dog ownership linked to lower mortality

November 17, 2017
A team of Swedish scientists have used national registries of more than 3.4 million Swedes aged 40 to 80 to study the association between dog ownership and cardiovascular health. Their study shows that dog owners had a lower ...

New shoe makes running 4 percent easier, 2-hour marathon possible, study shows

November 17, 2017
Eleven days after Boulder-born Shalane Flanagan won the New York City Marathon in new state-of-the-art racing flats known as "4%s," University of Colorado Boulder researchers have published the study that inspired the shoes' ...

Vaping while pregnant could cause craniofacial birth defects, study shows

November 16, 2017
Using e-cigarettes during pregnancy could cause birth defects of the oral cavity and face, according to a recent Virginia Commonwealth University study.

Study: For older women, every movement matters

November 16, 2017
Folding your laundry or doing the dishes might not be the most enjoyable parts of your day. But simple activities like these may help prolong your life, according to the findings of a new study in older women led by the University ...

When vegetables are closer in price to chips, people eat healthier, study finds

November 16, 2017
When healthier food, like vegetables and dairy products, is pricier compared to unhealthy items, like salty snacks and sugary sweets, Americans are significantly less likely to have a high-quality diet, a new Drexel University ...

Children's exposure to secondhand smoke may be vastly underestimated by parents

November 15, 2017
Four out of 10 children in the US are exposed to secondhand smoke, according to the American Heart Association. A new Tel Aviv University study suggests that parents who smoke mistakenly rely on their own physical senses ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

genastropsychicallst
2.3 / 5 (3) Dec 13, 2010
But when i'm walking i see much longer the womans.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.