how come drinking cold water feels refreshing, but cold water on your skin is shocking like a cold shower?

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how come drinking cold water feels refreshing, but cold water on your skin is shocking like a cold shower?

In: Biology

It’s because it’s cold, your body needs to stay a certain temperature to keep you alive so it’s telling you that “this is cold, cold is bad, cold is death”

I’d always seen it as an evolutionary response to drinking out of cold fresh springs or glacial melt run off. Less chance of disease vs warm, stagnant water.

Cold water in nature is *generally* cleaner (don’t go out drinking water that happens to be cold, please), whereas tepid water has probably sat and may harbor dangerous microbes. Drinking tepid or warm water is unpleasant, likely due to an evolutionary “memory” and preference for cool/cold water.

Conversely, there’s never been an evolutionary advantage to jumping fully into cold water–probably a contraindication even.

It’s because, as a first worlder, you are used to bathing in hot water. Plenty of people on the rest of the world bathe in cold water daily and it doesn’t feel shocking to them. And not just people in hot climates; the Inca bathed daily in cold water and they lived in high altitude mountains.

If you do it every day, you get used to it.

In addition to what others have said, one reason drinking cold water feels refreshing is that a cooling of the tongue is believed to be one mechanism for satiating thirst.

[https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162261](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162261)

The mechanisms to feel thirst have to do with the volume of water in your blood and organs and concentration of electrolytes in and around your cells. Drink a bunch of water, and those levels will balance out. But it takes 15-20 minutes for the water and electrolytes to get where they need to go, and for these changes to be registered by the appropriate sensory organs. If you continued feeling thirsty that whole time, you’d be in danger of drinking too much water and damaging your organs or dying. So the mechanisms that satisfy thirst (cooling of the tongue and possibly the muscle movements associated with swallowing liquid) are different than those of feeling thirsty (special organs that detect salt levels in the blood and low blood plasma volume).

As to why cold water feels shocking, this might be due to the fact that the same sensory receptors that register hot and cold also register pain (bare nerve endings in the skin, in contrast to the other sensory receptors that register pressure and vibration). This also might be why extreme hot and extreme cold can feel so similar — and feel painful.

Cold water feels refreshing because, especially when exerting yourself, your internal body tempature is rising. It’s not actually your body responding to the water. When the brain feels you giving it what it needs it rewards you with a release of endorphins as a way to encourage you to keep doing it. It’d your brains natural way of communicating with you.

As opposed to the skin well the outside of us our skin aka epiderminus is designed to detect changes in tempature quickly as a defense mechanism for potential dangers.

In addition if you ever had goosebumps on your skin this is actually left over from our early days when we were covered in a lot more hair. The goosebumps would help fluff out their hairs more to keep us warmer when cold as well as make us look bigger when scared to scare off potential predators

Drinking cold water keeps you hydrated and alive.
Being splashed with cold water or swimming in it and cause hypothermia and death.

It’s just those pesky evolutionary instincts keeping you alive.