Perhaps you’ve heard that men who work out a lot have lower sperm counts. If so, you’ve heard wrong, according to a study published in the British Journal of Sports Medicine.

Harvard researchers looked at the activity level and television viewing habits of 189 healthy men aged 18-22. They also determined the men’s semen quality, with measurements of sperm count, sperm concentration, motility, and morphology.

The researchers found that the most active men had the highest sperm concentration and sperm count. These subjects did 15 hours or more each week of physical activity, which the researchers defined as “moderate to vigorous exercise.” Their sperm concentration was 73% greater than the least active men in the study, who were active five or fewer hours per week.

But don’t get in from a 2-hour run and plop yourself in front of the television just yet. The researchers also found that the men who watched the most TV had the lowest sperm concentration. The ones who watched 20 hours or more per week had 44% lower sperm concentration than the men who watched no TV in an average week. Working out more, of course, leaves less time for TV, setting in motion a positive feedback cycle.