Ride a motorcycle, lose your wood, says a Japanese medical study.
Doctors in Japan surveyed more than 200 men who typically rode motorcycle for several hours at a stretch and found that more than two-thirds of them had problems achieving erections or emptying their bladders.
The medics said ordinary motorcycle seats put pressure on the area behind the scrotum, restricting blood flow to the penis. Vibration from the motorcycle engines also affected hormones that affect bladder function, so these men had trouble urinating, as well.
In the study, three-quarters of the men in their forties, and almost all of the men in their fifties, reported serious erectile problems. The same problems were reported about half as often among men who did not ride motorcycles.