How global warming and pollution weaken spermatozoa and male fertility
Italian research highlights how exposure to chemical and air pollutants and rising temperatures in cities have negative effects
Key points
Italy is one of the countries with the lowest birth rate in the world. An alarming statistic that is rooted in multiple socioeconomic and cultural factors, but also in often underestimated physiological causes. Among these, the impact of the climate crisis, rising temperatures and environmental pollution on male fertility stands out strongly .
Italian research published in the latest issue of the Journal of Assisted Reproduction and Genetics highlighted how exposure to chemical and air pollutants and rising temperatures in cities have negative effects on sperm quality.
"There is a lot of scientific work showing how these environmental pollutants, often defined as endocrine disruptors, can have a negative impact on reproductive health," explains Professor Daniele Gianfrilli, one of the authors of the study, an endocrinologist and expert in reproductive medicine at the Sapienza University of Rome. "But the element investigated now is that heat also plays a precise role: the rise in temperatures typical of cities, due to their conformation and lack of greenery, leads to a worsening of the quality of seminal fluid. The study analysed data from the past ten years on exposure to chemical pollutants, atmospheric particulate matter and high temperatures. The results show how these factors reduce sperm concentration, motility and morphology.
Why does heat damage fertility?
The functioning of the male reproductive system is particularly sensitive to temperature variations. Men's testicles, in order to function properly, must be at a lower temperature than the body temperature, 'so much so that they are in the scrotal sac, i.e. they are outside our abdomen, unlike women's ovaries, precisely because they have to be at a temperature one to two degrees lower,' Gianfrilli further emphasises.
So, when environmental temperatures rise steadily and prolonged, as is increasingly the case in cities due to climate change and heat waves, the testicles also suffer this thermal stress. 'By now, several studies show how the high temperatures to which some workers or those who frequently take saunas are exposed can affect sperm production,' adds the professor, highlighting how the effect, although reversible in certain cases, can have consequences on the fertility of the entire urban population.
