Cycling can double the risk of impotence, scientists said yesterday at the start of National Bike Week - an attempt to encourage the 10 million Britons who own a cycle but never use it to take to the road.
Scientists at University Hospital in Brussels found that male cyclists were twice as likely to be impotent as men who never rode a bike. Two thirds of both male and female cyclists reported discomfort in their genital areas - another sign of possible problems.
One in 10 men overall suffers from impotence, but among the 1,000 cyclists tested the rate was double that.
The link between cycling and impotence is controversial, with some experts believing that researchers have exaggerated the risks.
But Dr Irwin Goldstein, who published the first study on the issue in 1997, believes that cycling could have caused thousands of men to become impotent. Dr Goldstein, of the Boston Medical Centre, believes that the position a man sits in when cycling compresses the main artery in the penis, inhibiting the blood flow.
In the short term, this causes numbness, but over time the compression could narrow the artery and lower the bloodflow to the point of impotence.
Research published last year found that male mountain bikers were more likely to suffer from fertility problems. The frequent jolts and vibrations caused by riding over rough terrain are thought to reduce sperm counts.
The Belgian experts said cyclists should stand on their pedals every 10 minutes to relieve pressure on the genitals.
Meanwhile, more than 20,000 people took part in the annual 56-mile London to Brighton cycle ride yesterday, raising more than £2m for the British Heart Foundation.Reuse content