People who take cold showers tend to laud the many supposed benefits of this practice, from a quicker recovery after intense athletic activity to lowering your chances of getting sick.

But how much of this is based on science? Let’s explore the evidence for each of the common claims about cold showers and your body.

Most of the research around temperature and testosterone has to do with the testicles and scrotum. The scrotum hangs outside the body in order to keep the testicles at an optimal temperature to produce sperm and other hormones, around 95 to 98.6°F or 35 to 37°C.

The idea is that cold showers lower the scrotal temperature, allowing the testicles to produce a maximum amount of sperm and testosterone.

But the research says little about testosterone production. Rather, cooler testes have a stronger effect on DNA processes that result in higher sperm volume, quality, and motility (movement).

A 1987 study found that keeping the testicular temperature between 31 to 37°C (88 to 99°F) allowed optimal DNA, RNA, and protein synthesis. This results in better sperm production.

A 2013 study even found that cold winter temperatures improved sperm morphology (shape) and movement.

But sperm production and testosterone levels aren’t the same thing, and there’s some evidence to the contrary.

A 1991 study found that cold water stimulation had no effect on levels of testosterone levels, although physical activity did. A 2007 study suggests that brief exposure to cold temperature actually decreases testosterone levels in your blood.

Cold water isn’t going to do anything for your testosterone levels that exercise won’t do. Many other variables affect those levels, such as diet and lifestyle choices like smoking and drinking. A quick cold shower isn’t a testosterone level hack.

Let’s look at a little more research around fertility. A 2007 study found that reducing regular exposure to warm water improved several study participants’ sperm counts by an average of nearly 500 percent.

This doesn’t mean that cold showers do anything to improve fertility, though. Simply taking fewer hot showers boosts your sperm count and quality, since heat, in general, affects sperm production.

There’s no research to show that there’s any equivalent relationship of cold water exposure or hot water reduction with female fertility. The research only points to male fertility.

There’s some evidence that a cold shower might increase your energy levels.

A 2016 study found that participants felt like they had more energy after taking hot-to-cold showers for a month and then cold showers for another two months. The participants said it felt similar to a caffeine effect.

A 2010 study suggests that cold water immersion may help reduce the amount of energy your body needs to help you recover after a strenuous workout, lowering inflammation and increasing blood flow without expending extra energy.

Yes! Brown fat, or brown adipose tissue, is a type of fat in all humans, large or small.

Two studies, one in 2007 and another in 2009, found links between cold temperature and activation of brown fat. They also found an inverse relationship between brown and white fat (white adipose tissue).

Essentially, the more brown fat you have, the more likely you are to have a healthy amount of white fat and a good body mass index, one of the key indicators of your overall health.

Cold water may help you recover faster from a workout, but the effects may only be slight or overexaggerated.

A 2010 case report of two athletes, one a martial artist and the other a marathon runner, found that cold water immersion may help reduce pain and tenderness after intense exercise. It may also allow for a quicker return to athletic activities.

Two studies, one in 2007 and another in 2016, showed only a slight beneficial effect of cold water immersion on recovery from muscle soreness. This was especially the case when done back-to-back with hot water exposure, or done for at least 10 to 15 minutes in water at temperatures from 52 to 59°F (11 to 15°C).

Another 2007 study found no benefit to cold water exposure for muscle soreness.

Some research suggests that cold water exposure might have a small, but still unclear, effect on your immune system.

A 2014 study showed that immersion in cold water causes the body to release adrenaline. This has two effects: It makes your immune system produce more anti-inflammatory substances. It also lowers your inflammation response to infections. Both of these effects can help your body resist illness.

A 2016 study found that cold showers lowered the study participants’ absence from work by 29 percent. This suggests that cold showers may boost the immune system, even though there was no effect found on how long people were sick.

Here are some pointers to doing it in a way that’ll increase your chances of benefitting from this lifestyle change without hurting your body:

  • Start slow. Don’t bathe in ice-cold water right away. Gradually adjust the temperature throughout the shower or make each successive shower slightly colder than the last. Start warm, then lukewarm, then cool, then completely cold.
  • Don’t go all-in right away. Splash some cold water on your hands, feet, and face to get used to the temperature, instead of shocking your entire body with instant cold.
  • Have a towel or warm area ready. Once you’re done, make sure you can warm up right away so that you don’t start shivering.
  • Do it consistently. You probably won’t notice any changes right away. Take a cold shower every day at the same time so your body adjusts and becomes more likely to respond to consistent cold exposure.

Not everyone should jump right into a cold shower. People with the following conditions should avoid them:

If you have depression or a mental health condition, don’t replace your medication with cold water therapy.

If you live in a cold climate where exposure to cold water can lead to hypothermia, cold showers aren’t suggested.

Cold showers aren’t necessarily going to change your life with the turn of a faucet.

Changing your routine can make you more mindful of your body, your habits, and your overall lifestyle.

This holistic approach to your physical, mental, and emotional health can affect your entire life, including your testosterone levels, your energy levels, and your overall health and fitness.

Cold showers probably won’t hurt, although they’ll feel pretty intense the first few times. The benefits might surprise you. Just start slow, listen to your body, and adjust accordingly.