Man's Fertility may be Lowered by Heated Car Seat
Scientists warn that the seats could damage sperm production by raising men's temperature to unhealthy levels.
The study follows warnings that keeping a mobile phone in a trouser pocket for too long or extensive use of a laptop computer can also affect fertility.
An optimal temperature of between 35 and 36 °C is needed to produce healthy sperm.
Even small temperature changes can significantly affect sperm counts, which are why the testes are outside the body, which has an average temperature of 37 °C.
Scientists tested the effect of heated car seats on 30 healthy men.
Fox News adds, "Study authors said male fertility is at its peak when the core body temperature is below 99 degrees Fahrenheit. Volunteers agreed to twice sit at randomized times for 90 minutes on either heated or unheated car seats. Researchers found that after just one hour of sitting on a heated car seat, the average scrotal temperature increased to 99.5 degrees and one volunteer's temperature reached 103 degrees."
The volunteers were fitted with temperature sensitive sensors and asked to sit on different types of car seats for 90 minutes.
Reporting their findings in New Scientist, the team says that on unheated seats the average temperature of the scrotum was 36.7 °C.
But on the heated car seats one man's temperature rose to 39.7 °C, while the average was 37.3 °C.
Andreas Jung of the University of Giessen in Germany, who led the study, said that the average rise in temperature could be enough to damage sperm production.
The seats are found as standard or as an option in many popular cars including the Honda Civic, Ford Mondeo and Nissan Qashqai, and are becoming increasingly popular in Britain.
BMW estimate that last year they sold around 40,000 vehicles with heated seats, around one in three of all their British sales.
Male drivers have previously been warned that sitting in a car for long periods, even without a heated seat, can affect their fertility.
Earlier studies also suggest men who drive for longer than three hours a day can take longer to conceive with their partners.
Prolonged or regular exposure to higher temperatures can override the body's ability to keep the testes cool.
High temperatures can result DNA damage leaving men with a lower sperm count.
The sperm produced are also less able to swim as far.
More similar studies:
According to Allan Pacey; lecturer in Andrology at the University of Sheffield Department of Obstetrics and Gynaecology suggested that Occupational factors are perhaps the most important to consider, but although we know about the negative effects of a handful of chemicals, we are largely ignorant about most of the compounds that men come into contact with in the workplace. The assault on the testes does not have to be chemical in nature, however. Recent reports suggested that men who spend a long time driving might have lower semen quality, possibly as a result of their testicles becoming too warm. Once again this is controversial and before men desert their cars in favor of their bicycles, a similar report published last year suggested that too long in the saddle could also be bad for sperm production.
A man's testes need to be a little cooler than his body temperature in order to do a good job of making sperm. That's why they dangle outside his body in the scrotal sac. When trying to conceive, men should stay out of hot baths, hot tubs, and saunas. Even sitting at a desk or driving for a long time can make the testes too warm. What about wearing boxes vs. briefs? Although many people recommend boxers, medical evidence is sparse.
A study led by Louis Bujan at the Male Fertility Research Group at Hopital La Grave in Toulouse showed scrotal temperatures rise significantly in male drivers, accounting for at least some of the loss of male fertility. The testicles of male drivers heat up enough to have an impact on sperm production, and researchers believe the findings explain why the wives of taxi and lorry drivers find it harder to conceive than the partners of casual drivers. Studies have shown sperm counts falling by 1.5 to 3 per cent a year. Tighter underwear or a more sedentary lifestyle is unlikely to account for such a large decrease, scientists believe.
In 2000, doctors in France urged men trying to have children not to spend too long behind the wheel. It followed a study which found that driving for hours on end can damage sperm. The same may apply to those who cycle or work outside. Italian researchers have found that exposure to traffic fumes can damage sperm.
Excessive heat such as what you would experience from a fever, from sitting in hot tubs or excessively hot baths, or from occupations that require long periods of sitting (for example, long-distance truck driving) may reduce a man's fertility by interfering with sperm production; according to Overachiever's Guide which was published at WebMD.
Studies have shown that if testicles become too hot - for instance as a result of too many hot baths or long hours spent sitting driving a car - both testosterone and sperm production may decrease.
A recent study in France by the Eylau Centre for Assisted Reproduction found that there has long been conflicting evidence about the effect of temperature on fertility and tight clothing and although I was once sceptical I do think there may be a case for this. "In a recent study we found that men who wore tight pants were twice as likely to have sperm that were less efficient swimmers.” He adds: "Of course, plenty of men with tight briefs are fathers, so it's not an all or nothing situation. But if you're on the borderline of success, you could potentially change your fertility by swapping your briefs for boxers."