However, it’s worth mentioning that chronic exposure to extreme heat, such as in certain occupational settings, may have more pronounced effects on testosterone levels. However, there are various factors that can impact testosterone levels, including excessive exposure to heat, such as saunas. Yes, frequent and prolonged exposure to heat, such as from hot baths or saunas, can negatively impact sperm production and motility, which can affect fertility. However, it’s important to note that most studies show a temporary effect, and testosterone levels generally recover after the heat exposure ceases.
While some people might experience a noticeable LH boost from cold exposure, others may see little change. Cold water immersion might stimulate LH release, potentially paving the way for higher testosterone production. Even a brief 15-minute cold plunge at 50°F (10°C) can keep cortisol levels lower for up to three hours . By reducing overall body fat, brown fat activation may help lower estrogen levels, improving the testosterone-to-estrogen ratio . Research by Susanna Soberg highlights how cold exposure can transform white fat - typically metabolically inactive - into energy-burning brown fat . This process can indirectly affect testosterone levels by improving the testosterone-to-estrogen balance. This complexity makes it difficult to predict exactly how cold plunges will affect an individual’s hormone levels.
A different study had participants wear insulated jockstraps for six to fourteen weeks. The results were intratesticular temperatures of 40–42 ˚C (104–108 ˚F) and infertility. One study exposed participants’ testes to microwave radiation for thirty minutes every three weeks. The testes are covered by the cremaster muscle, which involuntarily contracts or relaxes to either draw the testes closer to the body for warmth or away from the body to cool. A 1994 meta-analysis found that the sperm density of smokers is on average 13 percent to 17 percent lower than that of nonsmokers, although the researchers were not able to identify a dose-dependent relationship between the number of cigarettes smoked per day and sperm density. Unfortunately, studies of such size are expensive and complex and therefore rare. Did you know that the average cisgendered male human produces approximately the same number of morphologically normal sperm per day as a hamster, despite having testicles ten times the size?
Prolonged exposure to high temperatures can lead to a temporary decrease in testosterone production. The question of whether hot baths affect testosterone levels is a subject of ongoing interest. Therefore, further research is needed to confirm the effects of repeated sauna-induced thermal stress on specific hormones and the relationships between different hormones (such as the T/C ratio). An increase in COR concentrations is considered a sensitive indicator of a stress reaction and intolerance of heat, which is most frequently reported in infrequent or first-time sauna users (Follenius et al., 1982). In the present study, a significant decrease in COR levels could suggest that users who regularly use the sauna (twice a week) are accustomed to extreme changes in temperature.
At least one study has found a dose-dependent response between male body mass index (BMI) and infertility. Hopefully, future studies will examine whether the small temperature changes in testes induced by tight bottoms are capable of influencing fertility. Studies have shown that when wearing tight underwear, testicular temperatures do increase.
Men and women seem to respond differently to cold exposure, though research on female hormonal responses is still limited. Sean Smiley, a 43-year-old man, saw his testosterone levels climb from the low 200s ng/dL to 595 ng/dL within 35–45 days . Even shorter exposures may temporarily lower testosterone, with factors like age, fitness level, and acclimation to cold playing a role. More extreme scenarios, like a 9-hour dive at 39°F (4°C) among military trainees, resulted in a significant decrease in total testosterone levels . Research indicates that cold immersion can suppress testosterone if not done correctly. These include the testes’ sensitivity to LH, the body’s ability to convert precursor molecules into testosterone, and the influence of other hormones.
The world of cold therapy is vast, and while it offers many benefits, it’s crucial to remember that each individual’s journey will be unique. Starting slow, listening to one’s body, and seeking guidance when necessary are paramount. For those intrigued by the promise of cold therapy, it’s essential to approach it with both enthusiasm and caution. Most studies have been centered on young male athletes, leaving a vast expanse of uncharted territory. This gradual approach reduces the risk of shock and allows your body to adapt safely.
Several studies have investigated the effects of heat on testosterone levels. Repeated exposure to hot and cold thermal stress significantly decreases COR levels in young men who are regular sauna users, but it does not induce significant changes in the concentrations of TES, PRL, or DHEA-S. Other studies demonstrated a less significant increase in COR levels in young women on day 14 of daily sauna use, which suggests that the body becomes familiarized with a hot environment (Pilch et al., 2003, 2007).