One of the first studies to examine the relationship between men’s workouts and sex lives has found those who strenuously exercise may have a lower libido than those whose workouts are lighter.

The study by researchers at the University of North Carolina – Chapel Hill asked 1,077 men to assess their exercise training habits and sex drive. The results were published in Medicine & Science in Sports & Exercise (MSSE) earlier this month.

The patterns the emerged from the study found men whose exercise routines were either light or moderate in intensity or duration were more likely to report moderate or high libidos. Men whose workouts were longer or more intense reported a decreased libido.

The New York Times reported previous small studies found suggested grueling exercises may blunt testosterone levels in a man’s bloodstream over the short and long-term. Other studies have also hinted to moderate amounts of physical activity increases testosterone production in men, and theoretically increase their sex drive.

Dr. Anthony Hackney, a professor of exercise physiology and nutrition at UNC and lead on the study, told the Times both physical fatigue and lower testosterone levels after exercise likely play a factor. He added he and his colleagues hope to begin experiments that track exercise, hormone levels and libidos to learn more about their interactions.

Hackney suggested if someone is concerned about his training impacting his sex life, he might try exercising a little less to see if his libido changes.

“Fertility specialists will often ask a woman about whether and how much she exercises,” Hackney told the Times. “Based on our data, we think they should also be asking the man.”