On hot summer days, when I drink water to quench my thirst, my body immediately responds by sweating in 5 to 10 seconds or maybe less. How does our body detect the presence of water in the stomach so fast. Does our body detect the sudden decrease in temperature of the stomach or is it by some other mechanism. Why do we sweat after drinking water in the first place. Is it to remove the excess water or to cool the body down on a hot day?

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    $\begingroup$ interesting biology experiment: lemon balm is one of the most comment garden herbs, that looks a bit like mint, and that grows in most gardens and wild. If you drink it in a tea, it causes immediate sweating. check wiki if you want. I tried some on a hot day and i was immediately cooled by profusive sweating. cool. anniesremedy.com/diaphoreticsudorific-property-39.php $\endgroup$ – aliential Sep 25 '18 at 13:26
  • $\begingroup$ Me too, same situation. Happy to see i am not alone $\endgroup$ – melchi Apr 1 '20 at 17:04

Not everyone sweats in seconds after drinking water in summer.

Also, sweating in seconds after drinking water is not likely due to water being absorbed (Nutrition Reviews, 2015):

Ingested fluids are not immediately available for assimilation into the body. They are initially stored in the stomach, and there is little net absorption of water or solute across the gastric mucosa.

There are a lot of receptors, including stretch receptors and various chemoreceptors, in the stomach, so your stomach will likely recognize water as water and signal the brain via the nervous system, probably via the visceral afferent fibers.

One of two things may then happen:

  • Your brain can perceive a sudden appearance of water in your stomach as stress and react with sweating, like when you are embarrassed or excited.
  • When dehydrated, you sweat less to prevent further dehydration; when your brain recognizes there is new water in your stomach, it can now allow the signals coming from warm skin to trigger sympathetic nerves to release some sweat to cool you down.
  • $\begingroup$ Thanks for the answer. Do you have any idea why this is more likely in summer? And not everyone? Why me? It's cool to know that we have chemoreceptors in the stomach. Is there any other normal day-to-day situation when we can be aware of the chemoreceptors in the stomach? $\endgroup$ – Kevin Selva Prasanna Jan 22 '20 at 4:22
  • $\begingroup$ If it's only in summer, it's more likely related to thermoregulation, as I suggested in my second hypothesis (in winter it may not be warm enough to sweat). Why not everyone? Because there can be great personal differences in how someone reacts to "stress" (water suddenly appearing in your stomach). It may be partially psychological. It's like when people are embarrassed or scared, but not everyone responds by sweating. Other examples or receptors: The stomach can detect the amount of calories in the food and releases only a certain amount of calories in a certain time into the intestine... $\endgroup$ – Jan Jan 22 '20 at 11:09
  • $\begingroup$ ...Stomach can detect toxins from spoiled food and signals the vomiting center in the brain, which induces vomiting. Most gastrointestinal receptors are associated with nutrients and satiety, though. $\endgroup$ – Jan Jan 22 '20 at 11:12

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