Sperm Quality Enhanced by Sleeping Naked
Researchers, in a report published yesterday in an online science journal, have found that a man’s choice of underwear makes a big difference to the quality of their sperm. It seems that airier, cooler underpants help preserve vital reproductive cells. And at night, wearing no underwear at all gives the best results. Scientists from Stanford University in California, United States
Of the group, those who wore loose boxer shorts during the day and no underwear in bed had 25 per cent lower levels of damaged genetic material/Deoxyribonucleic Acid (DNA) in their sperm compared to those who wore tight pants both at night and during the day. The researchers, who will present their findings at this week’s meeting of the American Society for Reproductive Medicine in Baltimore, suspect that heat is the reason for the effect. The scientists, led by Katherine Sapra of the NICHD, said: “Among men in the general population attempting pregnancy, type of underwear worn during the day and to bed is associated with semen quality.
“Reducing exposure for bed decreases DNA fragmentation; better semen quality parameters are observed in men wearing boxers during the day and none to bed.” Previous research has also found that men who sit with laptops on their knees for prolonged periods are more likely to have damaged sperm, an impact also thought to be linked to heat. Male fertility expert Allan Pacey, professor of andrology at Sheffield University, said that tight underwear is bad for sperm production – and encouraged prospective dads to choose loose undergarments.
“We have known for some time that men who increase the temperature of their testicles, either through the heat exposure at work or by wearing tight underwear, have poorer semen quality compared to men whose testicles are cooler,” he said. Although there is a clear link between underwear and sperm, Professor Pacey said that as yet there is no definitive proof that it affects birth rate. “What has never adequately been shown is whether men can improve things by changing the choice of their underwear, but this study, although quite small, goes some way to suggest that is true,” Pacey said.
Meanwhile, the importance of the basic heat factor is perhaps no better conveyed than in a 2012 paper entitled “Mild induced testicular and epididymal hyperthermia alters sperm chromatin integrity in men.” The authors of this paper worked with five 25- to 35-year-old French men who had at least one child to directly test the effect of heat on sperm production and sperm quality.
The five men in the study were asked to wear specially designed underwear for 14 to 16 hours a day for four months. The underwear kept the scrotum and testicles very close to the body (much closer than you’d get with, say, standard boxer briefs) and naturally heated the testicles by a significant amount relative to their normal state.
The men provided a sperm sample at several points leading up to the study, several points during the study and several points after. By three to four weeks into the experiment, sperm amount and quality had declined significantly. Even more striking, by the end of the study the sperm count for the men in this sample was at virtually zero. By the last visit, only three of the five men had any sperm in their ejaculate.