If the men who choose to sleep nude claim that it is a question of comfort, this choice can also be the best way to optimise the quality of their sperm. A recent study confirmed that heat in particular can damage sperm quality.
The choice of underwear worn by day and by night could therefore be a factor in determining the quality of a man’s sperm, according to a study completed by scientists in the University of Stanford in California and the National Institute of Child Heath and Human Development in the United States, published in the review Science Alert.
The work concluded that it is preferable for men to opt for large boxer shorts during the day and to sleep nude, which is significantly less damaging to the DNA in their sperm. “Among men in the general population attempting pregnancy, [the] type of underwear worn during the day and to bed is associated with semen quality,” explains Katherine Sapra, who headed up the study. She stated that “better semen quality parameters are observed in men wearing boxers during the day and none to bed.”
The research was completed on a group of 501 men who planned to become fathers, who were followed up over a period of one year, during which their choice of underwear and sperm quality was monitored. The results showed that the men who slept naked and wore boxer shorts during the day had 25% less DNA fragmentation (ruptures and lesions in the genetic makeup of the sperm) than others.
The cause was thought to be the heat generated in the testicles by tight underwear. “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,” explains Allan Pacey, an expert in male fertility at the University of Sheffield in the United Kingdom. In the future, scientists are considering researching whether fertility is also affected by choice of underwear, by observing the number and the speed of pregnancies of the participants’ partners, after the men switch to wearing looser underwear.
- Photo credits: © Cyril Comtat