Researchers are firmly against taking a cold shower on a hot day. For instance, Professor Adam Taylor from Lancaster University in the UK argues that cooling off this way can actually have the opposite effect.
Instead of preparing the body to release excess heat, “the sudden shock of a cold shower makes the body ‘think’ it should retain heat,” the scientist believes. This can be life-threatening for individuals with high blood pressure and heart conditions.
Moreover, there is a risk of organ damage if the body remains too hot for an extended period, although such occurrences are generally rare.
However, there is a widespread issue that washing in cold water can exacerbate: unpleasant body odor and unclean skin. Cold water is not effective at removing and breaking down sebum and other impurities.
Additionally, cold water tightens the skin, which 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). This temperature helps our bodily systems function properly. When the body gets too hot, the temperature regulation center in the brain starts sending nerve signals to the blood vessels and muscles in or near the skin, instructing them to activate cooling mechanisms.
If the body maintains a high temperature for too long, it can lead to organ damage. To keep the temperature optimal, the body employs several cooling methods. For example, it radiates heat into the environment through electromagnetic radiation. Approximately 60 percent of the body’s heat is lost this way.
Perspiration is another mechanism it uses, losing about 22 percent of heat.
When the air temperature exceeds our body temperature, sweating becomes the dominant cooling mechanism, explains Professor Taylor.
Remaining body heat can be lost through contact with liquids and conduction to solid objects that the body also comes into contact with.
To support these mechanisms, our blood vessels change diameter. Those closest to the skin dilate to allow more blood to flow and get closer to the relatively cooler surface.
Then, the body works to ensure blood circulation and the movement of heat from the inside to the periphery for cooling.
Why You Should Say “No” to Cold Showers
Of course, when it gets unbearably hot outside, these biological mechanisms start to falter.
While plunging into cold water after sun exposure may feel refreshing on the skin, this process does not effectively lower the body’s internal temperature. Additionally, this practice can be risky, as reported by the Daily Mail.
In response to cold, the blood vessels near the skin constrict, reducing blood flow to those areas. Thus, a cold shower has the opposite effect, as less blood reaches the skin’s surface. Heat is retained inside and around the organs instead of being expelled from the body. Essentially, the person is tricking their body into not cooling down but rather conserving heat.
Water at around 59 °F (15 °C) can trigger a cold shock response, leading to rapid constriction of the blood vessels in the skin that come into contact with the water. This shock raises blood pressure, as the heart must now pump harder to overcome the increased resistance.
This reaction can be extremely dangerous for individuals with underlying heart conditions, such as ischemic heart disease.
A hot shower is also a bad idea on a hot day. While some experts believe that hot water helps the body cool down faster, unfortunately, that’s not the case, says Professor Taylor.
Water hotter than the body will transfer energy in the form of heat to the body, potentially raising its internal temperature. What a heat-exhausted person truly needs is a cool or warm bath or shower. Scientists consider a temperature of 78-80 °F (26-27 °C) to be the most effective. It allows blood to approach the skin’s surface for cooling and is not so cold that it forces the body to retain heat.
And one more thing: if cooling is necessary, it should be gradual. Otherwise, the body’s thermoregulation system will be working in vain.