Not getting enough sleep may harm men’s sperm, a new study from Denmark says.
Men who slept poorly had lower sperm counts and fewer sperm that had formed correctly, compared with men who slept better.
"Given the facts that approximately 20 percent of all young men may have reduced semen quality, and that sleep disturbances are common and increasing in industrialized countries, the results of this study may have important public health implications," the researchers wrote in their article.
Future studies should look at whether interventions aimed at improving sleep might also improve semen quality, they said.
The researchers used data from 953 young men who were mostly in their late teens and early 20s. They asked the men how well they had slept in the previous four weeks, conducted blood tests to measure their hormone levels and analyzed their semen.
The researchers found that 15 percent of the men said they had found it difficult to fall asleep, and 13 percent of the men reported sleeping restlessly.