Apologies, I could have clarified that (then again my comment already was a wall of text).
The body does not absorb water passively but actively, and it's been known for a very long time that water with a bit of salt and sugar is absorbed faster. This has been crucial in reducing (especially child) mortality due to acute fluid loss from diarrhea due to, say, cholera[0]. (I personally find amazing that Robert K. Crane figured out the mechanism behind it in the sixties already[1])
Now, "proper" ORS, according to the WHO, is the following:
However, that is in the context of oral rehydration therapy:
glucose facilitates the absorption of sodium (and hence water) on a 1:1 molar basis in the small intestine; sodium and potassium are needed to replace the body losses of these essential ions during diarrhoea (and vomiting); citrate corrects the acidosis that occurs as a result of diarrhoea and dehydration.
So you can usually get away with not having the potassium and trisodium if the reason for dehydration is neither diarrhoea or vomiting.
This translates to a simple home recipe of:
1 liter (or 4.25 cups) of water
1/2 a teaspoon of salt (3 gr)
2 table spoons of sugar (30 gr) OR 1 table spoon of glucose (15 gr)
The reason for doubling the amount of sugar is that the active absorption of water relies on glucose, while regular sugar is made out of sucrose. Sucrose breaks down into equal parts fructose and glucose (both have identical chemical formulas but a different arrangement of the atoms).
Apologies, I could have clarified that (then again my comment already was a wall of text).
The body does not absorb water passively but actively, and it's been known for a very long time that water with a bit of salt and sugar is absorbed faster. This has been crucial in reducing (especially child) mortality due to acute fluid loss from diarrhea due to, say, cholera[0]. (I personally find amazing that Robert K. Crane figured out the mechanism behind it in the sixties already[1])
Now, "proper" ORS, according to the WHO, is the following:
However, that is in the context of oral rehydration therapy:
glucose facilitates the absorption of sodium (and hence water) on a 1:1 molar basis in the small intestine; sodium and potassium are needed to replace the body losses of these essential ions during diarrhoea (and vomiting); citrate corrects the acidosis that occurs as a result of diarrhoea and dehydration.
So you can usually get away with not having the potassium and trisodium if the reason for dehydration is neither diarrhoea or vomiting.
This translates to a simple home recipe of:
The reason for doubling the amount of sugar is that the active absorption of water relies on glucose, while regular sugar is made out of sucrose. Sucrose breaks down into equal parts fructose and glucose (both have identical chemical formulas but a different arrangement of the atoms).
[0] https://en.wikipedia.org/wiki/Oral_rehydration_therapy
[1] https://en.wikipedia.org/wiki/Sodium-glucose_transport_prote...
[2] https://www.who.int/publications/i/item/WHO-FCH-CAH-06.1 page 12 of the linked on that page (labeled as page 3)
Or any other solution with electrolytes (Gatorade, DripDrop) etc