Sperm are produced in a man’s testicles (also known as “balls”). The optimal temperature for sperm production is about four degrees cooler than the average body temperature.
The scrotum keeps the testicles at this cool temperature, but many men’s lifestyles can cause the temperatures in their scrotal sac to rise. This can damage sperm and lead to infertility.
Sperm are fragile little guys who have a tough job. They must dodge hostile white blood cells as they swim through the vagina to get to the egg, and they must be at a certain temperature in order to survive. That’s why they can’t live in a hot tub. In fact, a study conducted in 2007 found that even a few minutes of time in a hot tub or bath can ruin sperm.
The germ cells that produce sperm in the testicles need to be about two or three degrees cooler than normal body temperature. That’s why it’s important to keep the scrotum, or the skin sac that holds your testicles, cool. Anything that raises the scrotum’s temperature can destroy sperm, including hot tubs and jacuzzis.
A lot of men spend a significant amount of time in the tub or taking long hot baths, and this can damage their fertility. In one study, men who spent at least 30 minutes per week in a hot tub or long hot bath had a 22% lower sperm motility than those who didn’t use the bath.
Hot water can also cause the scrotum to become warmer by compressing the testicles, which in turn raises their temperature. Other examples of this are tight-fitting jeans or bicycle shorts that hold the scrotum close to the body.
A hot shower might be good for your skin, but it’s not great for sperm. Sperm cells like to be 3.5 degrees cooler than body temperature. So, long, hot baths and showers overheat the testicles and can be harmful to fertility.
Men with jobs that involve lots of heat, such as chefs or firemen who work in non-breathable uniforms might be better off taking tepid showers. In fact, even sitting for extended periods of time in a hot tub or sauna can be detrimental to sperm health.
For this reason, it’s a good idea to avoid the sauna when trying to conceive. It’s also a good idea to wear loose, light clothing and shorts instead of tight pants when trying to conceive. Tight pants push the testicles closer to the body and can cause them to overheat.
The good news is that once the scrotal temperature returns to normal, the sperm count and motility will too. If you want to be sure, have your sperm tested at a fertility clinic and look for a high sperm count, movement and a normal sperm shape and structure. If your sperm counts are low, there are treatments that can help. But you’ll need to be patient, as it can take months for sperm counts to return to normal after avoiding hot environments.
A long soak in a hot tub or bath, even on occasion, can overheat a man’s testicles. This overheating causes the testicles to lose their natural ability to produce high quality sperm.
Scientists agree that the scrotum should be about two degrees cooler than body temperature, in order to properly produce sperm. If the scrotum is too warm, the DNA inside sperm can become damaged due to increased “oxidative stress.”
Researchers from the University of Oregon found that the heat produced in a man’s testicles during hot tub use can lead to oxidative damage to the sperm. This can result in a decreased sperm concentration, reduced motility and changed sperm morphology.
Besides hot tubs, baths and long hot showers, men who have jobs that involve significant heat exposure (like bakers and ceramic oven workers) can also experience overheating of the testicles. In some cases, overheating can cause a decrease in semen parameters that may last for three months.
Fortunately, overheating caused by hot tubs, long hot showers or a job in a hot environment can be reversed with the right approach. Many infertile couples who reduce their exposure to hot tubs and long hot showers have reported improved sperm production and motility. This is an easy change to make that can be very beneficial for a couple trying to conceive.
There’s a reason your guy’s testicles (commonly known as his balls) are outside his body—they need to be cooler than his normal body temperature for optimal sperm production. That’s why the cremaster muscle contracts to pull his testicles close to his body if they get too warm, and relaxes to push them away if he gets too cold.
Spending time in hot tubs, jacuzzis and saunas, or taking long, hot showers or baths overheats his testicles and may significantly impair sperm function. In fact, some studies show that sperm count is negatively impacted by heat and may even be destroyed in some cases.
Sperm needs to be about 4 degrees cooler than your body’s core temperature for optimal sperm production. In addition, the testicles have a special “sleeve” that is able to move the sperm closer to your body for warmth when needed, and then back away again for cooling.
If he wears tight underwear or pants that hold his testicles close to his body, this can also increase his temperature and destroy sperm. So, if you know your guy is trying to conceive, make sure he skips the long soaks in the hot tub and opts for short, tepid showers instead. In addition, he should consider wearing loose boxer-style underwear to help his testicles stay cool.