File photo: The study recommended fertility consultants should ask male partners about how much they exercise if they are trying for a baby.

London - Men who do intense workouts have a lower libido than those who do less intense exercise, a study has found.

It said men reached a "tipping point" after which they are too exhausted or simply lose interest in having sex, and recommended fertility consultants should ask male partners about how much they exercise if they are trying for a baby.

"Fertility specialists will often ask a woman about whether and how much she exercises," said lead researcher Anthony Hackney. "Based on our data, we think they should also be asking the man".

The study on 1 100 men in the US was published in the journal Medicine & Science in Sports & Exercise. It said regular "exposure to higher levels of chronic intense and greater durations of endurance training is significantly associated with a decreased libido in men". 

While it identified the "tipping point" when exercise was detrimental to sex, it said more research was needed to say what it was.