Does a hot water bath reduce male fertility?

Various factors such as high ambient temperature in living or occupational environments and unhealthy living habits would increase the temperature of the scrotum therefore, inducing negative effects on sperm quality. It is urgent to develop suggestions and tactics to safeguard the health of people who reside in or work in hot environments, particularly their ability to reproduce since in a study of regular sauna bathers, the male reproductive function was disrupted and could be altered.

There have been several proposed biological mechanisms for how heat affects male fertility. In an interview with HT Lifestyle, Dr M Niharika, Gynecologist at Kamineni Hospitals in Hyderabad’s LB Nagar, explained, “When the ambient temperature is high, crystalline nitric oxide (NO), nitric oxide synthase (NOS), macrophage movement inhibitors (MIF), and sperm levels are also high. Chromosome condensation, Caspase-3 activity, and DNA integrity all rise. Although Caspase-3 (Cysteine-requiring Aspartate Protease) concentration is a crucial sieving enzyme for apoptosis. A different percentage of ejaculated sperm express other markers of end-stage apoptosis when Caspase-3 is activated and loses the integrity of DNA fragmentation.”

Addressing the question under fire and revealing whether a hot water bath reduces male fertility, she said, “Spermatogenesis is a complex, multi-step process involving the proliferation and differentiation of spermatogonia into mature sperm. During spermatogenesis, the optimal temperature of the testicles is 2 to 4 degrees C lower than body temperature. This is the reason why testicles are placed in a scrotal sac outside the abdomen unlike other organs. Living in a high temperature environment and unhealthy lifestyle can damage the sperms. Also the time of exposure to heat is important factor as just having one hot water shower or one sauna bath doesn’t damage the sperms immediately. If a patient is having repeatedly heat exposure to the scrotal skin directly in the case of hot water bath or sauna baths then definitely it is going to have an impact on spermatogenesis.”

She added, “Other factors that contribute to higher testicular temperatures include habits, lifestyles, wearing tight clothing, occupational factors (such as prolonged exposure to high temperatures), and climate change. Investigations into the relationship between high ambient temperatures and various sperm parameters in humans have produced conflicting and inconclusive results. In 2020, numerous studies demonstrated that heat stress increased the temperature of the testicular tissue, lowering sperm concentration and motility in people who had scrotal warming.”

Highlighting that the human sperm is damaged by heat stress because it loses viability, motility and density, the health expert elaborated, “Spermatogenesis is reduced by 14% for every degree C that testicular temperature rises. Sperm motility is significantly decreased by high ambient temperature due to decreased mitochondrial activity and ATP synthesis. Heat stress causes apoptosis in testicular tissue via mitochondrial pathways or DNA damage. Male infertility can also result from damaged sperm in the vas deferens DNA breaking under the influence of high ambient temperature. As a result, heat stress poses a significant risk to testicular tissue, sperm quality, and the risk of infertility. Significant sperm impairments, such as changes in sperm indexes, mitochondrial dysfunction and sperm DNA closure, are brought on by exposure to high temperatures in a sauna.”