Gaby
Experts advise against taking a cold shower on a hot day. Professor Adam Taylor from Lancaster University in the UK says cooling off this way can have the opposite effect.
“The sudden shock of a cold shower makes the body ‘think’ it should retain heat,” Professor Taylor says. That reaction can be life-threatening for people with high blood pressure or heart conditions.
There is also a small risk of organ damage if the body stays too hot for a long time, though such cases are generally rare.
Cold water can also make body odor and skin cleanliness worse. It’s not effective at removing sebum and other impurities.
Cold water tightens the skin and can trap sebum and dirt in the pores.
How Does Our Body’s Thermoregulation Work?
The optimal temperature for the human body is 98.6 °F (36.6 °C). That temperature helps our systems function properly. When the body gets too hot, the hypothalamus—the brain’s temperature-regulation center—sends nerve signals to blood vessels and muscles in or near the skin to activate cooling mechanisms.
If the body remains overheated for too long, it can lead to organ damage. To keep temperature in range, the body uses several cooling methods. For example, it radiates heat into the environment. Approximately 60 percent of the body’s heat is lost that way.
Perspiration accounts for about 22 percent of heat loss.
When the air temperature exceeds body temperature, sweating becomes the dominant cooling mechanism, Taylor explains.
The body can also lose heat through contact with liquids and by conduction to solid objects it touches.
To support cooling, blood vessels near the skin dilate to bring warm blood closer to the surface.
That helps move heat from the core toward the periphery so it can be lost to the environment.
Why You Should Say “No” to Cold Showers
When it gets unbearably hot outside, these biological mechanisms can start to fail.
Plunging into cold water after sun exposure may feel refreshing on the skin, but it does not effectively lower internal body temperature. This practice can also be risky, as reported by the Daily Mail.
In response to cold, the blood vessels near the skin constrict and reduce blood flow to those areas. A cold shower can therefore have the opposite effect: less blood reaches the skin’s surface, and heat is retained around the organs instead of being expelled. In effect, the body is tricked into conserving heat rather than shedding it.
Water around 59 °F (15 °C) can trigger a cold shock response, causing rapid constriction of the blood vessels in the skin that touch the water. That shock raises blood pressure because the heart must pump harder to overcome the increased resistance.
This reaction can be extremely dangerous for people with underlying heart conditions, such as ischemic heart disease.
A hot shower is also a bad idea on a hot day. Some people assume hot water helps the body cool down faster, but that’s not the case, Taylor says.
Water hotter than the body will transfer heat to the body and can raise internal temperature. What a heat-exhausted person really needs is a cool or lukewarm bath or shower. Professor Taylor says a water temperature of about 78–80 °F (26–27 °C) is most effective: warm enough to allow blood to reach the skin for cooling, and not so cold that it forces the body to retain heat.
If cooling is necessary, do it gradually. Sudden, extreme temperature changes can defeat the body’s thermoregulation.
