The human body has a nerve that is called the vagus nerve , The vagus nerve runs from the brain through the face and heart to the abdomen. If there is a violent alert for this nerve, such as cold water that is thrown in the stomach at once, this nerve might alert the heart and stops it from working.
There are many cases of sudden death due to a very severe alert to this nerve, and scientists have called this (neurotic prohibition), which leads to heart failure. Prophet Muhammad ( peace upon him) warned us from chugging water and recommended drinking at with three sips, and that was a guidance from God who created the human body.
Our body is just like any machine, imagine that it is too hot or making a hard effort and you poured a cold water on it; wouldn’t it break down ?! so is the human body , so try to drink water while sitting down and with three sips just like the Hadith said ” sit down when you drink and don’t chug water” .
It is also scientifically proven that the responsible for the feeling of thirst is the liver, and when chugging water at once, the water falls suddenly to the liver causing cirrhosis, but when drinking with three sips, the first one warn the liver that the water is coming so it gets ready by getting wet and soft and no corrosion occurs. Besides , it is from Sunnah to do so.
Thus drink water while sitting to help your body getting rid of all the harmful deposits, including deposits that cause kidney stones, when you sip a little then stop and breath , your body takes in oxygen and gives insulin to the blood, and insulin protects from diabetes.