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Heatwaves And Male Fertility: Sperm Health Statistics UK 2026
Heatwaves And Male Fertility: Sperm Health Statistics UK 2026
Dr. Zoë Lees (PhD)
Dr. Sophie Dix (BSc, PhD)
27 July 2026
How Do Heatwaves Affect Male Fertility? UK Sperm Health Statistics 2026
How do heatwaves affect male fertility? 10 findings from MedExpress (2026)
What is the link between heat exposure and sperm health?
How to improve sperm count: Expert advice from MedExpress
How to improve sperm health during a heatwave
Methodology
References
How Do Heatwaves Affect Male Fertility? UK Sperm Health Statistics 2026
UK summers are getting warmer, with extreme, record-breaking heatwaves becoming more frequent. In fact, the UK's 10 warmest years since records began in 1884 have all occurred since 2002. [1]
While the health risks of scorching temperatures are well documented, growing evidence suggests prolonged heat exposure may also affect male fertility.
Despite this, new research conducted by MedExpress, reveals that men’s awareness remains surprisingly low, with just one in five (21%) saying they strongly believe heat exposure can affect their sperm quality.
How do heatwaves affect male fertility? 10 findings from MedExpress (2026)
(MedExpress survey of 750 UK men, June 2026)
- Only 21% of UK men strongly believe heat can affect sperm quality.
- Around 50% of UK men actively trying for a baby change their habits during hot weather.
- 20% of UK men would continue to wear tight-fitting clothing during a heatwave.
- 53% of men wear breathable fabrics like cotton or linen during periods of hot weather.
- 52% avoid tight trousers or jeans during periods of hot weather.
- 37% sleep without underwear during periods of hot weather.
- 24% take more breaks from sitting during periods of hot weather.
- 32% of UK men strongly agree that clothing choices can affect testicular temperature.
- 34% strongly agree that looser-fitting underwear is recommended to help keep the testicles cooler.
- Only 21% of UK men strongly agree that sitting for prolonged periods can affect testicular temperature.
What is the link between heat exposure and sperm health?
One of the largest studies on the topic, analysing data from more than 54,000 men over 18 years, found exposure to heatwaves was associated with lower sperm counts and poorer sperm quality. [2]
The research also found that the longer a heatwave lasted, the greater the impact, with heatwaves lasting six days or more linked to the biggest decline in semen quality.
Separate studies also suggest that every 1 °C increase in testicular temperature may reduce sperm production by around 14%, highlighting how even slight rises in temperature can seriously affect reproductive health. [3]
How to improve sperm count: Expert advice from MedExpress
“Research shows that the testicles need to stay around 2–4°C cooler than your core body temperature to produce healthy sperm. [3] While that may sound complicated, maintaining testicular temperature doesn't require anything drastic.
“For men actively trying to conceive, making simple lifestyle changes during hot weather could play an important role in supporting sperm production and reproductive health.
“With prolonged heatwaves becoming more common in the UK, it's important men understand how extreme temperatures may affect reproductive health. Small, practical changes during hot weather could help reduce heat exposure and support sperm health, particularly for those planning to start a family."
- Doctor Sophie Dix, Head of Medical Affairs at MedExpress
How to improve sperm health during a heatwave
Dr. Sophie Dix recommends:
“Go commando” at night: Sleeping without tight underwear can improve airflow to the testicles and may help keep testicular temperature lower overnight.
Switch fabrics: Wearing loose, breathable fabrics like cotton or linen and avoiding wearing tight trousers or jeans during hot weather can help to maintain a cooler environment that supports healthy sperm production.
Take regular breaks from sitting: Long periods of sitting, such as working at a desk or driving, can trap heat around the groin area, particularly in warm environments. Standing up and moving regularly can improve airflow and help keep the scrotum cooler.
Avoid very hot baths: While baths aren't a complete no-go, keeping the temperature lukewarm rather than hot, or switching regular hot baths for showers, can help reduce repeated heat exposure to the testicles.
Keep laptops off your lap: Laptops can generate heat, and using them directly on your lap for extended periods may increase heat exposure around the testicles. Using a desk, surface, or even a cushion under your laptop can create a barrier and help keep the area cooler.
Methodology
We conducted a survey of 750 nationwide male representatives in June 2026.
References
- https://www.metoffice.gov.uk/blog/2026/how-has-summer-warmth-changed-in-the-uk https://www.metoffice.gov.uk/research/climate/understanding-climate/uk-and-global-extreme-events-heatwaves
- https://www.sciencedirect.com/science/article/abs/pii/S0048969724039603
- https://www.rbmojournal.com/article/S1472-6483(14)00545-8/fulltext
Next scheduled review date: 27 July 2029
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Authors
Written by: Dr. Zoë Lees (PhD)
Dr. Zoë Lees is a medical writer at MedExpress specialising in obesity and health communication. She completed her PhD at the University of Glasgow, where she investigated adipose tissue (fat tissue) function in pregnancies complicated by pre-eclampsia and gestational diabetes. Her work focuses on translating complex clinical evidence into clear, engaging and evidence-based health information for patients and the public. At MedExpress, Zoë contributes to clinical content, educational resources and media communications across areas including weight management, GLP-1 therapies and metabolic disease. Zoë is particularly interested in improving public understanding of obesity as a chronic condition and ensuring patients have access to accurate, accessible health information grounded in current scientific evidence.
Medically reviewed by: Dr. Sophie Dix (BSc, PhD)
Dr. Sophie Dix is Head of Medical Affairs at MedExpress. A behavioural neuroscientist by training, Sophie has spent 30 years working at the intersection of medical research, pharmacology, technology and patient communication across the pharmaceutical industry, health technology and charity sectors. At MedExpress, Sophie's role is to ensure that everything the organisation does is grounded in the most current science. That means translating complex clinical evidence into accessible health information across the website, clinical pathways and media communications. It also means working with external press and broadcast media as a named expert commentator, making the science behind weight management and GLP-1 treatments understandable to a general audience. A core part of Sophie's work is building MedExpress's Real-World Evidence (RWE) programme: learning systematically from patient outcomes to understand what works in practice, not just in clinical trials. This patient-level insight feeds directly into improving patient experience and health outcomes. Sophie believes that patients make better decisions when they have access to accurate, evidence-based information. As an advocate for meaningful change in how obesity is understood, Sophie works to reduce stigma and raise awareness of the condition as an illness. This includes reframing the conversation around GLP-1s from aesthetics to public health, while highlighting the health benefits of weight loss and weight management.
Note from the experts
Remember: This blog shouldn’t be regarded as medical advice, diagnosis, or treatment. We make sure everything we publish is fact checked by clinical experts and regularly reviewed, but it may not always reflect the most recent health guidelines. Always speak to your doctor about any health concerns you have.