Researchers have discovered that men who watch five or more hours of TV per day reduce the possibility of becoming a father by more than 30%.
1200 healthy young men were studied by experts from Copenhagen University in order to find out whether a sedentary lifestyle had any effect on fertility.
The results were published in the American Journal of Epidemiology, which showed that TV watchers had one-third less sperm per milliliter of fluid than those who hardly ever watched TV. Those who watched the least TV had an average sperm count of 52 million per milliliter of fluid, whereas the men who watched the most TV had as few as 37 million per milliliter of fluid. They also had lower levels of testosterone, which is the male hormone responsible for activating sperm production.
Interestingly, those who spent equal time in front of the computer did not suffer the same consequences, which leads to the belief that TV watchers generally exercise less and eat less healthily than others.
Regular exercise and a healthy diet are vital for male fertility, with an average of 15 hours of exercise per week boosting the count and quality of sperm, according to a 2013 study in the US.
What affects fertility? 
Over the last two decades, several studies have raised concerns over the decline in men’s sperm count, which has been blamed on junk food diets, traces of the contraceptive pill in drinking water, and BPA, a chemical used in some plastics.
However, a Danish research team has discovered that the biggest factor could be the laziness and lack of health associated with men’s new TV habits. Between 2008 and 2012 young males joining military service were interviewed and tested, with viewing habits and sperm samples shared as evidence. Sperm counts varied from 40 to 300 million per milliliter of fluid, with a low count being registered as anything below 15 million.
The results were clear: those who watched the most TV had a significant reduction in sperm count, having as much as one-third less than those who did not watch much TV.
Are there other health concerns? 
Recent studies linked TV-watching to an increase in the risk of developing blood clots in the lungs, which triggered the fertility research.
The studies showed that every extra two hours in front of the TV increased the risk of dying from a pulmonary embolism by as much as 40%! Watching more than five hours per day resulting in doubling the risk of mortality compared to those who watched 2.5 hours or less.
According to recent polls, as much as 50% of Britons confessed to never doing cardio, and 25% said that they did one hour or less per week. This means that only one-quarter of adults in the UK are exercising for more than one hour per week, whether it’s running, swimming, cycling, golfing, or simply walking.
While exercise is recommended to boost fertility, researchers have also pointed out the risk of harming sperm cells from excessive biking or long periods spent in tight clothing. The testicles are generally 2ºC cooler than the rest of the body, and in tight clothing, they could overheat and decrease sperm count.
Sources:
https://www.popline.org/node/478315
https://bjsm.bmj.com/content/early/2013/01/21/bjsports-2012-091644.short
https://www.rbmojournal.com/article/S1472-6483(15)00144-3/abstract?cc=y=
https://clinicalepigeneticsjournal.biomedcentral.com/articles/10.1186/s13148-016-0217-2
https://aje.oxfordjournals.org/content/early/2016/08/07/aje.kwv338.abstract
