The Effect of Saunas on Reproductive Function

Science tells us: it’s not that simple. Among Finns and Japanese, who have a long-standing and deeply rooted sauna tradition, fertility is not reduced compared to other countries. However, there is a «but».
Temperature is a critical factor for spermatogenesis. The testicles are located outside the body for a reason: they require a temperature 2-3°C lower than body temperature. When this condition is disrupted, sperm quality deteriorates.

A study by Garolla et al. (2013) showed that men with normal sperm parameters who visited a Finnish sauna twice a week for 3 months at a temperature of 80-90°C, sperm count decreased by more than half, and motility significantly deteriorated. At the same time, no changes in sex hormone levels (testosterone, FSH, LH) were detected. An important detail: six months after stopping sauna visits, all parameters fully recovered. In other words, the sauna does not cause any irreversible damage to sperm.

These same conclusions are confirmed by a broader review by Huhtaniemi & Laukkanen (2020): acute heat exposure in a sauna does indeed temporarily reduce spermatogenesis, however, the chronic impact of saunas on fertility remains less clear-cut: as we have already mentioned, sperm counts in Japan and Finland are no lower than in other countries.

A large prospective study by McKinnon et al. (2022) involving 3,041 couples planning a pregnancy found that isolated sauna use had no statistically significant effect on the probability of conception per cycle. However, the combination of several sources of heat exposure at the same time (frequent hot baths, prolonged sitting, a laptop on the lap, heated car seats) moderately reduced this figure, especially in men over 30.

So, from a man’s perspective, if a couple is actively planning a pregnancy, it’s worth limiting regular sauna visits or taking a break while trying to conceive.

But when we turn to women, the picture is much more interesting and the opposite! First of all, no persistent infertility was found in women who regularly visit the sauna over a long period of time.

For women over 35, whose fertility is already naturally reduced, the sauna may even have a moderately positive effect through other mechanisms. Fedorchenko (2025) notes that regular sauna visits (2-3 sessions per week) reduce cortisol levels by 20-25%, which decreases stress-induced suppression of the hypothalamic-pituitary-ovarian axis, critical for ovulation. Improved blood supply to the pelvic organs can support ovarian and uterine function, promoting follicle development and implantation.

So, when it comes to saunas and fertility, here’s the picture: while saunas clearly have a positive impact on health, their relationship with fertility is nuanced. For women, it can even be beneficial – as a way to reduce stress and improve blood flow. For men, regular sauna use temporarily reduces sperm quality – but this effect is reversible and, according to available data, does not affect actual fertility when used in moderation.

So, enjoy the sauna!