True or false - cycling can make men infertile?

Cycling just five hours a week ‘could damage a man’s fertility’” – that was a Daily Mail headline in 2010. But is there any truth to this claim? The Daily Mail article included findings from a research project at Boston University.

This pertinent study observed 2,261 men over 10 years - from all walks of life and not just elite athletes - who contributed over 4,500 samples of sperm. Investigators correlated the sperm health with the level of exercise, focusing on sperm density (the number of sperm per millilitre), sperm motility (the percentage of sperm that were moving), and sperm morphology (what the sperm look like).

The study found that men bicycling more than five hours per week had a lower sperm concentration than either sedentary men or those doing other types of exercise.

31% of the cyclists had a low sperm count, compared with 25% of the non-exercisers.

40% of cyclists had sperm with low motility, compared with 27% of the sedentary men.

Possible causes for lower sperm concentration among cyclists

Long-distance bicyclists support a high percentage of their body weight on the perineal area between the testes and the rectum. The increased scrotum temperature and perineal trauma can affect blood flow to the testis, which can also negatively impact the production of sperm.

Impact on the testicular and perineal area may impact sexual function. Studies show significant nerve or vascular injury in some individuals who bicycle intensely or for long periods.

Genital numbing may persist in some men for a long time after cycling, which can significantly affect sexual function. Bicyclists also report erectile dysfunction.

Should you stop or reduce cycling whilst trying to conceive?

Not necessarily! There is another side to this argument. In 2014 scientists at University College London undertook the largest ever study of cyclists and found no link between the sport and infertility.

Their study of more than 5,000 men found no impact on fertility, even when they routinely cycled more than eight and a half hours per week. In fact, the study found that men who cycled between 3.76 and 5.75 hours a week had a decreased risk of infertility.

The myth that cycling can make men infertile stemmed from credible research, but it has since been overthrown by more expansive research. Thus, if you're a man looking to conceive and you enjoy cycling, there is no need to give up. Just ensure you take a look at the practical advice at the bottom of the blog, then pedal away!

My husband Charlie and I have a son who turns 1 in May 2021 and at some stage we'd like to try for a second child. Charlie and I are keen triathletes, entering a handful of races each year - Sprint, Olympic and Half Iron Man distances. However, when we decide to try for baby number two we'll train at a lower level so our bodies aren't in a state of physical stress from an intense training regime.

Practical advice for male cyclists trying to conceive

You can modify your position by finding the appropriate saddle height, saddle shape, and handlebar height, all of which can impact the amount of pressure placed on the genital area. Increasing the width of the back part of the seat, which supports the bony parts of the pelvis, may help to take some of the pressure off of the genital area. Choose clothing that is comfortable and gives good airflow to your genital area to keep it cool.