Heat's impact on male fertility

A recent study highlights the substantial risk extreme heat poses to male fertility, marking a significant concern amid global warming trends.

Euronews Green reports.


In short:

  • Scientists from Singapore found that exposure to extreme heat significantly increases the risk of low sperm count and concentration, with sperm mobility also affected.
  • The research suggests that men in their prime reproductive years, specifically between 25 and 35, are the most vulnerable to these effects.
  • Recommendations include avoiding excessive heat, saunas, hot baths, and wearing tight underwear to protect sperm health.

Key quote:

"So just because you're a young male, don't think you're invincible, and don't think you're not also vulnerable to these impacts."

— Dr. Samuel Gunther, Yong Loo Lin School of Medicine

Why this matters:

The testicles, where sperm production occurs, are particularly sensitive to heat. Prolonged exposure to high temperatures can disrupt this delicate process, leading to decreased sperm count, impaired sperm motility (movement), and changes in sperm morphology (shape and structure). This can ultimately reduce a man's ability to father children.

Research has shown that heat stress can also damage the DNA within sperm, increasing the risk of genetic abnormalities in offspring.

And it's not just heat — chemicals in our environment are disrupting our hormonal balance, causing varying degrees of reproductive havoc as well.

Climate change is accelerating health threats worldwide

Climate change is accelerating health threats worldwide

The Lancet Countdown - established in 2016 to annually assess the effects of climate change on health - released a ten year report and accompanying editorial.


In short:

  • For the first time, the report quantifies heat-related deaths attributable to climate change, estimated at about 370,000 a year. The past 11 years have been the hottest ever recorded.
  • The report examined 54 indicators of climate change-driven health impacts and found that many health threats had increased or accelerated over the past decade.
  • Populations least responsible for climate change are experiencing the highest impacts.


Key quote:

“Over the past 10 years, a strong evidence-based case has been made that responding to climate change could be the greatest health opportunity of the 21st century.”



Why this matters:

The report points out how fossil fuel interests are blocking progress on climate change. It tracks not only heat-related deaths, as mentioned above, but also other climate related effects on health caused by floods, landslides, droughts, viruses, and more. It also tracks improvements, for example, estimating that the transition to clean energy prevented 400,000 deaths in 2023 just through improved indoor air quality. Health professionals are trusted sources of information and can speak for policy change and action for a healthier future.


Related EHN coverage:


More resources: The Lancet Countdown on health and climate change


Source:

Romanello, Marina et al. (2026), The 2026 report of the Lancet Countdown on health and climate change: a decade of escalating health harms and a decisive moment for all. The Lancet.

Related editorial, Climate change and health: 10 years on, what next? The Lancet.

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