High-altitude hiking, sleep apnoea and other conditions which deprive a man’s testes of oxygen, could be contributing to a decline in fertility over the past 50 years, a new study has suggested.The review article, published in the journal Nature Reviews Urology, explored how exposure to low oxygen levels can impact sperm quality and overall reproductive health of men, revealing that ‘testis hypoxia’ could be critical to declining male fertility.
Infertility in men refers to an inability to achieve pregnancy after at least 12 months of regular unprotected sexual intercourse, while sub-fertility represents a less severe situation, whereby one’s chances of conceiving are lowered.
A lack of oxygen in the testes, or testis hypoxia, caused by chronic medical conditions — such as sleep apnoea or varicocele — can be a sustained threat to reproductive health, lead author, Tessa Lord, a reproductive biologist and senior lecturer at The University of Newcastle, Australia, explained.
“Varicocele, or enlarged veins in the scrotum, is a common abnormality which is diagnosed as the cause of infertility in up to 45 per cent of men who are struggling to conceive,” Lord said.
Obstructive sleep apnoea is a common disorder, in which muscles in the throat narrow the airway during sleep, thereby affecting one’s breathing and blood oxygen levels. Cases have been shown to increase, with obesity being a key risk factor.