If you're trying for kids and want your sperm in the best possible shape (or even if you just want to brag about having healthy sperm), you need to find the right balance of sleep.
A preliminary study in the journal Fertility & Sterility suggests that snoozing for 7 to 8 hours a night seems to be best amount for sperm health.
The study analysed nearly 700 couples for one year and found that men who slept for less than 6 hours a night were 31 per cent less likely to impregnate their partners than men who slept between 7 and 8 hours.
Also, men who slept for more than 9 hours were 49 per cent less likely to get their partners pregnant, too.
As the study relied solely on pregnancy as the indictor of sperm health, it's not clear how shorter or longer periods of sleep is affecting your semen.
It's possible that under-sleeping can cause a drop in testosterone, a hormone vital for production of sperm. The reasons why over-sleeping could be damaging your sperm are a little less clear, but it could possibly have to do with poorer sleep quality which also affects testosterone.
Men in the study who had trouble sleeping uninterrupted throughout the night were also 28 per cent less likely to impregnate their partners. Another possible reason behind this is men with poorer quality of sleep also have other habits which damage their sperm like drinking, smoking and being overweight.
Improving the quality of your sperm is no quick-fix, however, as sperm cells mature around the 70 day mark so it may take between 2-3 months to experience a fertility boost from the time you start improving your sleeping habits.