With parts of Britain set to bask in temperatures of 34C from tomorrow, many will be dreading the prospect of sleepless nights – but that’s the least of your worries if you’re a man.
As overnight temperatures in some parts of the UK have reached nearly 20C (68F), research suggests even an increase of one degree can reduce the quality of sperm cells and affect fertility.
The study analysed semen samples from more than 6,600 donors worldwide over a six-year period.
On average, the mercury reached highs of between 6.7C (44F) and 18.2C (64.8F) across the nations sampled – with the highest being 42.1C (107.8F).
And the results showed those living in hotter climes had less sperm motility – the ability of the cells to move effectively, which is crucial for successful fertilisation.
The research might make for difficult reading for men living in some cities as London, Birmingham, Liverpool and Manchester are all set to see high temperatures.
The UK Health Security Agency has also issued a yellow heat health alert from 12pm tomorrow until Wednesday at 6pm
But those living in Scotland and Northern Ireland may rest a little easier as temperatures are expected to stay below 20C.
With parts of Britain set to bask in temperatures of 34C from tomorrow, many will be dreading the prospect of sleepless nights – but that’s the least of your worries if you’re a man
As overnight temperatures in some parts of the UK have reached nearly 20C (68F), research suggests even an increase of one degree can reduce the quality of sperm cells and affect fertility
The reason for the results of the study remain unclear but the researchers suggest that if the testes become warmer it could cause some cells to die and reduce the quality of remaining sperm.
The study, published in the journal Biomedical and Environmental Sciences, also suggests poor sleep on hot nights could impact on sperm quality.
Professor Raj Persad, at Bristol Urology Associates, suggested the results could explain a drop in the global birth rate.
‘It suggests that we might be able to improve fertility rates where it is consistently hot at night,’ he said.
Human testes are between 2C and 4C cooler than the body’s core temperature, which is critical for healthy sperm production.
The research, published in the journal Biomedical and Environmental Sciences, suggests that if the testes become warmer it could cause some cells to die and reduce the quality of remaining sperm. It also suggests poor sleep on hot nights could impact on sperm quality
This study, by Chinese researchers, is thought to be the first to look at the impact of overnight temperatures. Recent studies have shown a decline in global fertility rates, with one reporting a 10 per cent decline in sperm quality over the last 16 years
Previous studies have found a single degree rise in their temperature can reduce sperm count by around 40 per cent – while a two degree rise can reduce it to near zero.
Some seasonal studies in Europe have found that sperm output drops to around 70 per cent during the summer compared with winter. In general, fewer babies are conceived in the summer.
But this study, by Chinese researchers, is thought to be the first to look at the impact of overnight temperatures.
Poor semen quality has been identified as the most common cause of male infertility.
Recent studies have shown a decline in global fertility rates, with one reporting a 10 per cent decline in sperm quality over the last 16 years.
Recommendations to mitigate the problem include wearing loose-fitting underwear overnight and using electric fans.
But here’s the scientifically proven formula to stay cool
By Pat Hagan
The mercury is climbing again and Britain is basking in yet another heatwave.
But if you’re wondering how best to stay cool in the sweltering conditions, fear not – scientists have come up with the perfect formula.
The trick is to use an electric fan to cool the body’s exterior, while drinking the right amount of cold water for your weight – to ensure you don’t overheat inside.
Researchers from Heibei Vocational University of Technology and Engineering in Xingtai, China, found that the body cools best when someone sits near a fan and downs 6ml of cold water an hour for every kilogram they weigh.
For someone weighing 90kg – or around 14st – this equates to 540ml of cold water, or just under a pint, every hour.
A person weighing 60kg, or just under 10st, would need to drink around 360ml an hour – or two-thirds of a pint.
This researchers found that this method was the best way to lower body temperature, minimise sweat loss and reduce blood pressure and heart rate.
Drinking smaller quantities of water while using a fan – or just using a fan on its own – was much less effective, according to results published in the Journal of Thermal Biology.
If you’re wondering how best to stay cool in the sweltering conditions, fear not – scientists have come up with the perfect formula. The trick is to use an electric fan to cool the body’s exterior, while drinking the right amount of cold water for your weight
Researchers from Heibei Vocational University of Technology and Engineering in Xingtai, China, found that the body cools best when someone sits near a fan and downs 6ml of cold water an hour for every kilogram they weigh
The Chinese researchers recruited 14 young men and subjected them to eight hours of extreme heat exposure – with temperatures averaging 36.5C (97.7F).
At different times they either had no cooling aids at all, just used a fan, or had a fan and access to different quantities of cold water.
Fans helped but without drinking water simultaneously they increased the risk of dehydration, the study found.
And too little cold water failed to stem the negative effects of heat on the body.
In a report the researchers said heatwaves will become a bigger threat to health – especially as many homes are not equipped with air conditioning.
