Researchers noted in a Fertility and Sterility journal that sitting for 90 minutes in a heated car seat may not be as luxurious as expected. Because sperm are dependent on a constant temperature lower than that of body temperature, direct heat from seat heaters may have long-term effects on male fertility.

Ideally, sperm production occurs at around 93.2 F (34 C). This is 5.4 F (3 C) below normal body temperature of 98.6 F (37 C ). But your testicles can get too cold for good sperm production, too.

Goodness Gracious, Great Balls of Fire

The above is an expression, and part of the lyrics of a Jerry Lee Lewis song popularized in a 1957 record release, which is actually an old Southern saying, meaning “OMG” or “Holy Cow.” But if you are at all athletically inclined or able to work up a sweat, you might experience a sensation whereby your testicles seem to be abandoning your body – lowering to escape spermicide caused by too much body heat.

Next time you hear a guy address another, “How’re they hangin’?” you might be reminded that nature has imbued testicles with the ability to sense variations in body and outside-of-body temperatures. They rise to the occasion of a lower outside air thermometer reading, and descend when the opposite happens within the body.

This actually is also the case with mammals in general. Sperm production is intrinsically dependent on the temperature of the testicles. Sperm is best produced when testicles are below body temperature. The scrotum, you know, that pouch of skin containing the testicles is the regulator. Kind of the mechanism to protect the species survival, you might be inclined to think.

Expansion and contraction allow heat transfers between blood that flows into the testes via spermatic cord arteries. Blood also flows out via veins in the same cord. Results?  The blood is cooled or heated before entering the testes. There are, of course, limits to temperature control.

In extreme heat, this natural cooling mechanism may not be sufficient to prevent testicular temperature rise that can cause the quality and quantity of sperm produced.  Most unsafe heat exposure occurs in occupational situations. 

“A number of studies have demonstrated an association between sperm quality and heat exposure. A large case control study found that men exposed to heat because of their occupation were 1.8 times more likely to have morphologically abnormal sperm. They were also 1.8 times more likely to have been trying unsuccessfully to conceive for more than one year, than men who had not been occupationally exposed to heat.

Studies have also demonstrated that the following occupational groups have a higher risk of infertility, which is thought to be related (at least in part) to testicular heat exposure.”*

Another study, from the ASRM (American Society for Reproductive Medicine), discussed the influence of a heated versus an unheated car seat on scrotal temperature. This study suggests that the frequent use of a heated car seat represents an additional scrotal, and consequently, testicular heat stress factor to that which is present by merely sitting for long periods.

“It is too early to (make) any conclusions concerning the influence of heating car seats on semen quality,” researchers told Reuters Health.**

Another more recent comprehensive evaluation (of relevant articles published between 1970 and 2017) cited “Hypogonadism and erectile dysfunction can be associated with sports with high rates of head injuries, such as American football. Although early reports linked other sports, such as bicycling, to erectile dysfunction, subsequent studies isolated these associations to sports cycling rather than recreational cycling. Certain sports (football, basketball, handball, and volleyball) were linked to increasing prevalence and severity of varicocele, offering a potential link to male infertility. In addition, recreational activities such as sauna, hot tubs, Jacuzzis, heated car seats, and laptop use were associated with high testicular temperature, which can impair spermatogenesis. Radio frequency electromagnetic waves from cell phones and laptops have also been shown to have deleterious effects on sperm viability and motility.” ***

* https://healthengine.com.au/info/effect-of-environmental-factors-on-sperm-health

** https://www.reuters.com/article/us-heated-seat/heated-car-seat-may-be-too-hot-for-men-idUSCOL66403220080916?feedType=RSS&feedName=healthNews

*** https://www.eu-focus.europeanurology.com/article/S2405-4569(18)30103-2/fulltext

The Boston Medical Centers & Your General Health

Having treated hundreds of thousands of men worldwide, Boston Medical Group physicians understand both the physical and psychological effects of sexual dysfunction. With that in mind, all of Boston Medical Group medical centers are built with individual waiting rooms to create comfortable and private patient experience. 

All visits are by appointment only to limit the number of patients in the office at any given time. Further, The Boston Method® is designed so that all testing and treatment is completed right there in the office without the need for any off-site travel. https://www.bostonmedicalgroup.com/the-boston-method