Bicycling and (in)fertility

Researchers speaking at a recent European fertility conference told listeners that long hours in the saddle may be linked to infertility. They studied 15 triathletes in an attempt to determine whether swimming, running, or cycling had an affect on sperm count, and found that only cycling had a direct correlation. They also found that the more time a rider spent training, the lower their count. From an article in the Guardian:

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.

The good news is that average bicyclists riding to-and-from work, or running errands on the weekend, have little to be concerned about:

Allan Pacey, senior lecturer in andrology at the University of Sheffield, said there had been considerable interest among the cycling community in recent years about whether or not too many hours in the saddle might affect male fertility.

“However, it is important to stress that even if the association between cycling and poor sperm morphology is correct, men training for triathlons are spending much more time in the saddle than the average social cycler or someone who might cycle to and from work,” he said. “There is no evidence that men who ride a bike are less fertile than other males. Indeed, if you look back in our history, only 40 years ago cycling was much more common and there is no evidence from that time that men were less fertile. In fact, quite the contrary! The post-war baby boom proves that.”

Read the story in the Guardian

16 Responses to “Bicycling and (in)fertility”

  • tdp says:

    Whew! Thank Gawd I thought they were going to debunk the study! “Baad spermie!”

  • George Swain says:

    Another great reason to ride long distances! Enough kids already. Thanks!

  • jameasmallon says:

    Yeah, but these are Triatheletes. The sperm are giving up in disgust.

  • EdL says:

    How much do you want to bet that the lower sperm count has more to do with the number of hours spent in bike shorts rather than the number of hours necessarily being on the bike.

  • Ron says:


    The people with these troubles are riding litte ass-spatula saddles which are just too narrow to support a person’s sit bones. To compound the problem, they spend a good deal of time up on the nose of the saddle, especially when climbing or sprinting. Infertility is the lesser result from this habit. Sliding forward on the saddle may give a rider a powerful feeling on the bike, but he’ll feel a little less potent when he gets off (or tries to).
    Happy Trails,
    Ron Georg

  • bongobike says:

    That’s why we should all ride properly set up Brooks saddles :) I think as long as your saddle is not causing numbness or pain “down there” you should be OK. Otherwise ride a recumbent and fuggedaboutit!

  • lewis says:

    Does this mean that triatheletes will soon be extinct?

  • adam says:

    I agree, it’s probably the bike shorts, not the bike.

  • Lovely Bicycle! says:

    Bike shorts + saddle + the extra chemical supplements that many are said to be taking

  • WestfieldWanderer says:

    How many kids has Chris Boardman got?
    5 or 6? I forget.

  • Duncan Watson says:

    I am currently riding about 300km/week, roughly 186miles. The number varies but it goes from 150 to 200 miles or (241km-321km). But I have no fear of this issue. Mostly because all of my mileage is on a recumbent lowracer – picture.

    Of course recumbents are completely banned from triathlons. I am a cyclist not a tri-athlete. But I hate running anyway. Swimming long distances and open water pose no fear for me, but my knees hate running distances.

  • jameasmallon says:

    “Does this mean that triatheletes will soon be extinct?” Ha,we can only hope! But a greater terror awaits: the rise of the recumbants!

    In truth, I think it might be the shorts as much as hard narrow saddles. I gave up both, and have nothing but recommendation for merino boxers (under shorts) and Brooks saddles (even the narrower ones). Hey, without the silly shorts, not only can your sperm swim, you are more likely to meet the woman who’ll take you seriously enough to let them swim!

  • William says:

    I’d like to see a similar study of long distance tourists riding on traditional, relaxed bikes with decent saddles. I ride about 600-1000 miles a month, sometimes significantly more, and worry about this issue more than I’d like to at age 25.

  • Cullen says:

    I’m sure the same doesn’t apply to recumbent bikes…

    So, that means, whether we like or not, recumbent cyclists can have TONS of kids – more than upright cyclists.

    Good or bad?

    Cullen Carter
    Appleton, WI

  • Roland Smith says:

    Those long and pointy things that racers sit on would be more aptly named nutcrackers than saddles.

  • Quote of the Day: Fertility was Higher when Bicycles were Popular « The Sexify Blog *in Seoul* says:

    […] seems to be borne out by this less scaremongering article in the Guardian, via EcoVelo. Triathletes systematically cycling over 300km a week are, it reports, at risk of low sperm counts […]

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