Excessive heat can affect sperm, but that does not mean you can’t enjoy a sauna every once in a while. Here are some of the details.
How does overheating of the testicles affect sperm cells?
Male testicles are "outside" the body and maintain a temperature two to four degrees lower than other body parts. Spermatozoa are better produced under cool conditions, while high temperatures can cause disruptions [1]. But external overheating is not so much to blame as internal. Certain conditions, such as varicocele (varicose veins of the scrotum), can cause the temperature of the testicles to remain elevated.
Are things like saunas, heated seats, or tight and hot underwear harmful?
In the past, it was believed that external heat sources affected sperm, and there was some evidence that pointed to that. Such as a famous study conducted in 2013 that asked male volunteers to visit a sauna twice a week. During this time, some of the volunteers showed a lower sperm count, but it turned out to be temporary [2]. Other researchers have written that the testicles can overheat with the use of car seat heaters. Still others report that tight underwear can reduce sperm quality [3, 4].
Over time, data accumulated, and it became clear that overheating of the testicles can temporarily worsen sperm count but does not lead to infertility [5]. Other factors constitute a much more significant influence, including obesity and a sedentary lifestyle.
Does this mean that you can visit the sauna every day?
It is unclear how much outer heat exposure is safe. Some health organizations give vague advice, such as keeping the scrotum area cool and not frequenting the sauna if you plan to start or grow your family [6].
