Guys, for the sake of your sperm’s health, you may want to ditch that TV remote and head for the gym more often. A new study reports that the observed general decline in semen quality over the past few decades is most probably due to the increasingly sedentary lifestyles of young men.

Study details

The research, published in the British Journal of Sports Medicine, involved 189 healthy young college men aged 18 to 22; 58.4% of whom had a normal BMI (below 25kg/m2). The subjects were asked to report how many hours a week they engaged in vigorous, moderate and mild exercise and the average number of hours they had spent watching TV per day over the previous 3 months. Other factors that also influence sperm quality such as diet, stress levels, reproductive health and smoking habits were also analysed — the majority of the respondents (77.4%) did not smoke.

Time in Front of the TV

Once again, a sedentary lifestyle seems to be the bête noire: the researchers found a significant association between TV watching and sperm quality. According to the study, men who viewed over 20 hours of TV a week had less than half (44%) the sperm count of those who watched almost no TV. And while this may be a chance finding, the number of hours watching TV appears to impede the favourable effects of exercise, unlike weight and smoking.

It’s not that Doctor Who is thwarting your chances of becoming a dad but all this sitting may very well be affecting your little swimmers. The scientists postulate that being physically inactive increases oxidative stress levels which may have an adverse impact on male fertility.

And according to Allan Pacey, PhD, chairman of the British Fertility Society, the findings reinforce what fertility experts already know: excess heat is a bummer when it comes to sperm health. “We know that men who wear too tight underwear have poorer sperm. So it’s not a million miles away from sitting on the sofa … for too long and heating up your testicles for too long. It’s the same mechanism I would suspect.”

Influence of exercise

Not surprisingly, young men who engaged in moderate to vigorous exercise regularly — 15 hours or more per week — had a 73% higher sperm concentration compared to men who exercised less than 5 hours a week. Moderate to vigorous activity refers to any type of exercise that makes one “somewhat to very winded or sweaty”, explained the study authors. Light physical activity did not have any effect on sperm count, irrespective of frequency.

Furthermore, the scientists reported that men who were the most physically active were also more likely to have a healthy diet as opposed to those who watched a lot of TV.

Male fertility not necessarily at risk

While physical inactivity may diminish sperm count, the authors stated that this does not necessarily lower a man’s chances to father a child. What the research indicates is that an active lifestyle may be an easy, all-natural way to enhance semen quality and overall health.


    Gaskins et al (2013) Physical activity and television watching in relation to semen quality in young men. Br J Sports Med. doi:10.1136/bjsports-2012-091644.