Early bed-timers are almost four times more likely to have good-quality sperm to make their partners pregnant than late sleepers, a study has found.
Scientists asked men what time they had typically gone to bed over the past month, and if a doctor had found them to have normal or low-quality sperm.
Those who went to bed before 22:30 hours were almost four times more likely to have normal sperm than men who slept at 23:30 hours or later with the report stating that getting enough sleep was crucial.
Evidence suggests sleep deprivation can cause the immune system to overreact and attack sperm, while going to bed too late may see couples run out of time to have sex, according to the study.
Professor Hans Jakob Ingerslev, co-author of the study from Aarhus University, said: “These were men who had been trying to have a baby for about two years and an early bedtime was likely to be important because it allowed them to get more sleep.”
“The reasons could be psychological as sleep-deprived men suffer more stress and that can have an impact on fertility,” he said.
Dr Raj Mathur, a consultant gynaecologist at Manchester University NHS Foundation Trust, who was not involved in the study, said: “The study suggests men who are trying for a baby should be going to bed early and getting a decent amount of sleep.”
Researchers found men who went to bed ‘early’ before 22.30 hours were 2.75 times more likely to have normal sperm than those with a more ‘regular’ bedtime between 23:00 hours and 23.29 hours.
It said men who slept for between 7-and-a-half and eight hours more often had normal sperm, boosting their ability to have a baby naturally.
The results suggested they were six times more likely to have good-quality sperm than those who slept less than seven hours a night on average.