The average volume of blood in a 150 pound individual is about 5 liters. If you drink 1 liter of water, then you just diluted the blood and thereby decreased the blood glucose concentration by ⅙, or about 17%. I have found that drinking water in quantity is an effective first line defense and remedy for slightly elevated blood glucose (hyperglycemia).
For example, if I get a reading of 150 mg/dL, and I drink 1L (one liter) of water in 10 minutes or so, then within 10 minutes, my blood sugar will respond by dropping 10-15%, down to 135-140 mg/dL, within my acceptable postprandial (after meal) range. I find that this hydrotherapy is faster and safer than insulin therapy (1 unit of rapid insulin subcutaneously will lower glucose concentration by about 20 mg/dL over the course of 2 hours for me personally).
I find that the power of hydrotherapy is most helpful on a low or zero-carbohydrate diet, because any episodes of hyperglycemia are usually not more than 150-170 mg/dL, and can thereby be brought back into range with 1-4 liters of water consumed in a short amount of time. I can’t speak to it’s effectiveness with a high-carbohydrate diet, because the swings in blood glucose concentration are more dramatic and harder to control.
I add a few pinches of sea salt of Himalayan salt to my filtered water to ward off mineral deficiency. If I find myself experiencing leg cramps at night, then I know I am mineral deficient and take appropriate action through supplementation with Epsom salt (magnesium sulfate) in my drinking water.