But now it appears that watching too much television isn't just bad for our hearts, waistline or self-esteem, as a new study published in the British Journal of Sports Medicine claims it's also bad for young males' sperm.
The study collected data from 189 men between the ages of 18 to 22. Researchers reviewed their diets, physical activity, and the amount of television they watched, and found that men who watched more than 20 hours of television a week had a 44 per cent lower sperm count than the men who didn't.
And men who exercised for at least 15 hours a week at a "moderate to vigorous" rate had a 73 per cent higher sperm count than those who exercised fewer than five hours per week.
The researchers call these findings "pretty impressive differences."
"Our findings suggest that a more physically active lifestyle may improve semen quality." says Jorge Chavarro, assistant professor of nutrition and epidemiology at the Harvard School of Public Health.
It should be noted that none of the men had sperm counts that would be cause for alarm. The research team ruled out smoking and obesity as contributing factors among study participants.
"One of the things that we know is that when you engage in moderate to strenuous exercise on a regular basis, serum testosterone increases," Warren Foster, a professor in the department of obstetrics and gynaecology at McMaster University in Hamilton tells CBC News. "Serum testosterone…is involved in sperm production. As a consequence of that, one would expect to see that the more fit you are, you would potentially see a modest increase in semen quality."
National Geographic reports that low sperm count is linked to infertility, testicular cancer, prostate cancer, and cardiovascular problems later in life.
Some experts suggest that sperm counts have been dropping all over the world for some time now. Recently, Reuters reported that French men experienced a 32 per cent drop in sperm count between 1989 and 2005.
"A decline in male reproduction endpoints has been suspected for several decades and is still debated all around the world. Geographical differences have been observed between countries, and between areas inside countries," says Joëlle Le Moal from the Institut de Veille Sanitaire in France, who led that study.
Other researchers are looking for a connection between sperm count and environmental factors, but not all scientists are convinced there's a global sperm-count problem.
"Some scientists question whether sperm counts are falling at all: They blame changing lab tests, inconsistent study designs and other factors for the reported declines," USA Today reports.
Watch the video below on tips for men to increase their sperm count.