The Impact of Testicular Hyperthermia, Its Physiological Relevance and the Ability of Antioxidants to Overcome the Condition

Testicular heat stress is a well described phenomenon that occurs in mammals that possess a scrotum. Different models to induce testicular hyperthermia, such as surgical cryptorchidism, hot water bath, scrotal insulation or increased environmental temperature have all shown that spermatocytes and spermatids are unambiguously affected by high temperature, resulting in poor sperm production weeks later. Furthermore, a body of evidence suggest the involvement of oxidative stress is either a major or contributory pathway, which gives rise to the potential to overcome this condition. Whilst experimental models conclusively show the deleterious effect of testicular heat on sperm quality, the physiological relevance of the work is still debated. Herein we summarise a cohort of studies that report the effect of “season” on sperm quality. The data show season can affect sperm production, motility and morphology depending on where the work was performed. In countries where temperatures drop below zero, there is evidence showing summer conditions tend to improve semen quality. However, in sub-tropical countries, some studies show a decrease in summer, whilst others show no change. Herein we offer a reasonable explanation for this apparent controversy and present a range of antioxidant supplements that may offer some protection against testicular hyperthermia.