Male fertility is constantly decreasing. Live sperm production in European men has decreased by 50 percent in the last 30 years, and the density lessens by two to four per cent each year. However, this is not merely a European phenomenon. Testosterone production is decreasing significantly worldwide when compared to prior centuries.
The modern lifestyle is largely to blame for the deterioration of male fertility, as it has a negative impact on the male genitals. Poor nutrition, lengthy time spent sitting and clothes that are too snug and warm are all factors that hinder the healthy metabolism of genitals.
Tight Underwear Impairs Sperm Quality
Good blood flow and ventilation of the lower body is essential to maintain the health of sexual organs. Genitals should not be cramped in order not to disturb the blood circulation in the soft tissues. Tight clothes can lead to overheating of the testicles, which impacts sperm quality negatively. Pants that are too tight can force sexual organs into the warm body, where the sperm in the scrotum can be destroyed because of heat build-up. Wearing standard underwear creates a temperature of up to 37 degrees Celsius in the testicles when the ideal temperature should only be about 33 degrees.
US-Study Finds a Correlation in Those Who Sleep Naked and Those with Increased Fertility
Researchers at Stanford University and the National Institute of Child Health and Human Development (NCIHD) in Maryland came to this conclusion. The study was done with 500 men in a time frame of 12 months, wherein scientists observed the sperm quality of these men as it related to what underwear they were wearing during the day and at night. The researchers discovered, that men wearing boxers during the day and sleeping in the nude at night, had 25 percent less DNA fragmenting (damaging of the genetic material in sperm), than the men who wore underwear both day and night. The conclusion is that DNA fragmenting is decreased when the genitals are not confined by tight underwear at night. This is caused by the fact that male sexual organs are heat sensitive, which leads to impaired sperm production in the testicles at higher temperatures. For this reason, the researchers advise men to sleep in the nude and to wear loose-fitting underwear during the day, in order to keep the sperm cool and increase fertility. Allen Pacey, a leading fertility expert and Professor of Andrology at the University of Sheffield, remarks that it has been known for quite some time that men with increased temperature in their testicles, whether through heat in the workplace or tight underwear, have poorer sperm quality than those who have kept their testicles cool. However, up until now it was not known whether changing the type of underwear worn could help the situation. According to Pacey, it is important to investigate whether changing to loose fitting underwear leads to a pregnant partner more often or quicker than when sticking with tight underwear. Even though there is a clear correlation between the type of underwear worn and sperm, there is to date no concrete evidence, that it also influences the birth rate.
Another study conducted in the ’90s and published in the medical journal Lancet observed 12 men for one year who alternately wore tight and loose underwear. With this information, scientists were able to compare sperm quality with regard to underwear. The results showed that while the men were wearing tighter underwear, the sperm count was only half that seen during the time they wore loose underwear. The number of mobile sperm was only one-third bigger than in those wearing tight underwear.
More research is needed in the future in order to observe the exact impact of underwear on sperm quality. In the meantime, men who wish to have children or are concerned for their sperm health should wear loose fitting underwear or do without completely—especially at night—in order to protect their fertility.