10 healthy Finnish men in their 30s, all of whom had normal sperm counts and no history of sauna use in the past year, participated in the study, which involved completing a three-month sauna regimen, with 15-minute sessions twice every week. At each point in the study, the men provided blood and semen samples and researchers also recorded the participants’ scrotal temperature before and after each session.
At the end of the three-month sauna regimen, the results of which were published in the journal Human Reproduction, the researchers discovered that participants’ sperm count and concentration were lower and these numbers remained low three months after the men stopped visiting the sauna. This didn’t affect the men’s sexual health for very long, however, as at six months their sperm production wellness was restored to normal levels.
It makes sense that regular exposure to sauna heat would lead to reduced sperm count, as it is well-established that higher temperatures interfere with sperm production. By the end of each sauna session, the men’s scrotal temperatures increased an average of 5 degrees Fahrenheit. Dr Andrew Kramer, a urologist at the University of Maryland Medical Centre, explained, ‘The testicles hang down from the body in men to cool them,’ and if the testicles are heated by even several degrees, sperm production declines.
Other studies have shown that if you wear tight trousers, keep a laptop on your lap for long period or use hot tubs frequently, your sperm count may also reduce temporarily. Recent research has even shown that sperm production is highest in winter, and this too may possibly have something to do with temperature. However, your sperm count does not necessarily correspond to your fertility, as this is measured by the shape and speed of your sperm’s movement (motility). In other words, quality may be more important than quantity. However, if you are worried about sperm health, lay off the saunas (and other heated environments) for a few months.