Prolonged TV viewing linked to lower sperm count
Sperm motility (how well it swims) and shape were unaffected.
Warm lap
The researchers say their findings are not conclusive but suggest that men who want to improve their fertility might want to look at increasing the amount of physical exercise they do if they currently do little.
It is not clear why sitting on the sofa watching TV might lower sperm count. It might be down to temperature - sperm prefer cooler conditions and production halts if the scrotum gets too hot.
Obesity may also affect fertility - although most of the men were not overweight.
Low sperm count Environmental causes
Overexposure to certain environmental elements can affect sperm production or function. Specific causes include:
Industrial chemicals. Extended exposure to benzenes, toluene, xylene, herbicides, pesticides, organic solvents, painting materials and lead may contribute to low sperm counts.
Heavy metal exposure. Exposure to lead or other heavy metals also may cause infertility.
Radiation or X-rays. Exposure to radiation can reduce sperm production. It can take several years for sperm production to return to normal. With high doses of radiation, sperm production can be permanently reduced.
Overheating the testicles. Frequent use of saunas or hot tubs may temporarily lower your sperm count. Sitting for long periods, wearing tight clothing or using a laptop on your lap for long periods of time also may increase the temperature in your scrotum and reduce sperm production. The type of underwear you choose to wear is unlikely to significantly impact your sperm count.
Prolonged bicycling. Prolonged bicycling is another possible cause of reduced fertility due to overheating the testicles.
Dr Audrey Jane Gaskins and colleagues say more studies are needed to confirm and explore the possible causes behind their findings.
Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said: “It remains to be seen if coaxing a TV-watching couch potato into doing some regular exercise could actually improve his sperm count. Or whether there exists an unknown fundamental difference between men who like exercise and those who do not which might account for the findings.
“This should be a relatively easy study to perform, but before all worried men hunt for their sports bag it’s important to note that other research suggests that doing too much exercise can be harmful to sperm production.
“My advice would be everything in moderation - and that includes time in the gym as well as watching TV.”
###
BBC News