The researchers looked at 790 couples and found that men who slept less than six hours or more than nine hours saw a 42 percent reduction in fertility, compared to men who slept for eight hours.
The researchers suggest that hormones could explain the association. Testosterone is crucial for reproduction and most of it is released during sleep. Numerous studies have linked sleep time to testosterone levels.
Although the study only demonstrates an association, the link still remained even after adjusting for the participants’’ age and other factors that could impact fertility such as body mass index. The researchers suggest that sleep habits could also impact a person’s lifestyle habits during waking hours.
The researchers recommend that doctors discuss matters of sleep duration as a means to boost fertility outcomes when counseling couples looking to conceive.