There’s nothing attractive about a couch potato. It’s one thing to have some down time enjoying a favorite sitcom, but staying sedentary for hours on end, eyes peeled on a TV screen, is not only mind-numbing, it’s also not healthy.

Past studies have shown the correlation between mindless eating and a distinct lack of interest in exercise, with endless hours of sitting on the couch. And now research shows that being a couch potato may cause other physical problems as well.

Appearing in the British Journal of Sports Medicine, the recent study analyzed the diet and exercise habits of almost 200 men ages 18 to 22. Participants were also asked to provide sperm samples.

The investigators found that men who watched television for 20 hours per week had about a 45 percent lower sperm count than those who watched very little or no TV.

Exercise also seemed to be a mitigating factor. Men who worked out for 15 or more hours each week had a 73 percent higher sperm count than those who averaged five or less hours a week hitting the treadmill.

Despite these findings, the researchers acknowledged that the lowered sperm counts did not mean that couch potato men would not be able to father children. Rather, they said the study showed that reasonable exercise could alter a man’s physiology enough to help improve testicular health.

And researchers say reasonable is the key word. Previous studies have shown that too much vigor in a workout can also be dangerous and affect semen concentrations in a negative way as well.

Given that too much exercise or too little exercise might be detrimental, the best advice is to use moderation in any workout regimen … or in any plans to be a couch potato.