The growing interest in health is driving many people to seek ways to improve sleep, appearance, physical and mental performance, and even hormone levels and fertility.
As these tips spread on social media, practices such as saunas and cold water immersion have become very popular, with claims that they may raise testosterone levels, improve sperm health, and increase the chances of conception.
However, scientific evidence does not support all of these claims. Some studies indicate that excessive heat exposure may negatively affect sperm production, while there is insufficient evidence that exposure to cold improves fertility.
Much of the content circulating on the internet confuses testosterone levels with male fertility, although the two are not synonymous.
Testosterone is essential for the normal functioning of the male reproductive system, but a higher level of it in the blood does not necessarily mean more sperm production or increased chances of conception.
In fact, testosterone use as a treatment can suppress sperm production. Therefore, the American Urological Association and the American Society for Reproductive Medicine advise against testosterone therapy for men who wish to preserve their current or future fertility.
Therefore, any practice promoted as raising testosterone cannot automatically be considered a means of improving fertility.
The testicles are located in the scrotum outside the abdominal cavity, which helps maintain a suitable temperature for sperm production.
A large study involving more than 15,000 Chinese men and analyzing more than 28,000 semen samples showed a link between exposure to extreme temperatures and reduced semen quality, including lower sperm concentration, total sperm count, and motility.
These results do not mean that every sauna session leads to reduced fertility, but they are consistent with other evidence suggesting that heat exposure can affect sperm production.
A small Italian study provides more direct evidence of the sauna's effects. Ten healthy men underwent 15-minute Finnish sauna sessions twice a week, at temperatures between 80 and 90 degrees Celsius, for three months.
The results showed a decrease in sperm count and motility, along with changes in mitochondrial function and sperm DNA packaging. However, these changes were not permanent, as the indicators returned to normal six months after discontinuing sauna use.
In another study that followed couples trying to conceive, hot bathing alone was not associated with a significant change in pregnancy rates. However, men who were frequently exposed to more than one heat source had a lower chance of becoming pregnant.
It may seem logical that exposure to cold could reverse the effects of heat, but the available evidence does not prove this.
A systematic review by Australian researchers found that immersion in cold water may help reduce muscle soreness and speed recovery after strenuous exercise. Another review also pointed to potential benefits related to stress, sleep, and quality of life.
However, neither review found evidence that immersion in cold water raises testosterone levels, improves sperm quality, or increases pregnancy rates.
Furthermore, the study of localized scrotal cooling as a potential treatment for male infertility differs from full-body immersion in cold water. There is also no evidence to suggest that applying ice after a sauna can counteract the effects associated with heat exposure.
Therefore, immersion in cold water may be beneficial in some aspects of post-exercise recovery, but there is not enough scientific evidence to consider it a way to improve fertility.
Social media also circulates a lot of advice about improving women's fertility, often revolving around so-called hormonal balance, egg quality, and improving the chances of getting pregnant.
However, scientific evidence in this area remains limited. A systematic review by American researchers found that the effect of heat on the female reproductive system has not been adequately studied, with limited research conducted on humans.
Research on cold exposure relies heavily on animal studies. Therefore, it remains unclear whether immersion in cold water affects ovulation, egg quality, or a woman's chances of becoming pregnant.
Pregnancy remains a different case, so pregnant women or those with concerns about their reproductive health should consult a healthcare professional.
Health benefits do not necessarily mean improved fertility.
Current evidence suggests that saunas and cold water immersion may have other health benefits, such as relaxation, improved sleep, or aided recovery after exercise. However, these benefits do not automatically mean that the practice itself improves fertility.
For most healthy adults, occasional exposure to saunas or cold water is unlikely to affect their fertility. The problem arises when wellness practices are touted as sure-fire fertility boosters without sufficient scientific evidence.
Fertility is a complex process, and raising testosterone levels or tolerating high or low temperatures does not necessarily improve the chances of conception. It is best to view these practices as part of a healthy lifestyle, not as a proven fertility treatment.
