The results suggest that men who get less than six hours sleep a night, go to bed after midnight or have over nine hours sleep each evening are more likely to have damaged sperm.
The optimum amount of sleep for healthy fertility levels was seven to eight hours.
For the study, scientists divided 981 healthy Chinese men into groups according to research-set bedtimes and sleep durations.
Group A had a 8-10pm bedtime, group B went to sleep after 10pm and group C went to sleep after midnight.
They were also categorised in terms of their sleep durations - group one had a short sleep (less than six hours), group two had an average sleep (seven to eight hours) and group three had a long sleep (more than nine hours).
Sperm shape, count, survival and motility were examined according to sleep patterns.
Researchers also analysed the antisperm antibody production (ASA) in semen. These are naturally occurring antibodies which can cause problems with fertility.
They discovered that sperm counts and their survival rates were lower in people who had less sleep each night, compared to others in the group.
Going to bed after midnight and sleeping too much was also found to affect sperm quality.
Semen motility (how well it moves) was lower in short sleepers, compared to the average and long sleepers. They were also found to have a greater incidence of ASA.
The scientists concluded that “short and long sleep durations and late bedtime were associated with impaired sperm health”.
Professor Geeta Nargund, medical director of Create Fertility, told HuffPost UK that the study confirms the findings of previous studies showing an association between sleep disturbances and sperm quality in men.
“However, we need further studies to understand the mechanistic explanations and to assess whether sperm quality improves after interventions to restore sleeping patterns,” she added.
“Where necessary, we need to advise men to improve their lifestyle in order to protect their fertility.”