Have you had enough to drink?

[JohnL]

Actually, I believe it is sodium that will speed the absorption of the water, not sugar. Excess sugar above about 8% will actually slow down the absorption.

JohnL

There are two main factors that affect the speed at which fluid from a drink gets into the body:

> the speed at which it is emptied from the stomach
> the rate at which it is absorbed through the walls of the small intestine
The higher the carbohydrate levels in a drink the slower the rate of stomach emptying. Isotonic drinks with a carbohydrate level of between 6 and 8% are emptied from the stomach at a rate similar to water. Electrolytes, especially sodium and potassium, in a drink will reduce urine output, enable the fluid to empty quickly from the stomach, promote absorption from the intestine and encourage fluid retention.

 

[DougPaul]

Actually, I believe it is sodium that will speed the absorption of the water, not sugar. Excess sugar above about 8% will actually slow down the absorption.

JohnL

There are two main factors that affect the speed at which fluid from a drink gets into the body:

> the speed at which it is emptied from the stomach
> the rate at which it is absorbed through the walls of the small intestine
The higher the carbohydrate levels in a drink the slower the rate of stomach emptying. Isotonic drinks with a carbohydrate level of between 6 and 8% are emptied from the stomach at a rate similar to water. Electrolytes, especially sodium and potassium, in a drink will reduce urine output, enable the fluid to empty quickly from the stomach, promote absorption from the intestine and encourage fluid retention.

Do you have a credible reference for this info?

My reference is:
Kelly Cordes, "Liquid Lunch", Rock and Ice 102, Aug/Sept 2000, p 52.
Author info:
Kelly Cordes' exercise physiology masters's thesis at the
University of Montanna delt with hydration and thermoregulation.

According to my reference, the sugar concentration, up to a point, increases the absorbtion rate. Too much will slow it. The purpose of the the sodium and potassium is to replace that lost in sweat.

Doug

 

[Lovetohike]

Great thread. One strong consideration that I don't think has been specificallyi mentioned, but is an important consideration primarily in warm weather extended exercise. That is hyponatremia, i.e. a condition that results from taking in too much water while exercising. This can result in a very serious dilution of electrolytes and severe problems (cardiac, etc.) It also is more prevalent, I think, in cases when just plain water is taken in, vs. water plus electolytes, but I think it can happen even when some electrolytes are taken in with the water. One guideline I read is that the average recommendation is around 28 oz. per hour, with variations depending on the weight of the person and exact conditions. And, many of these studies were done with marathon athletes, etc. However, an interesting finding was that the runners in the top group tended to hydrate o.k., and the runners in the middle and back tended more towards overhydration. Don't think it would be a problem at all in winter, where this thread started, but it has wandered into hydration in general and it's important to bring this aspect into consideration. Here is a one link I found that gives some pretty extensive detail on this issue. Very interesting discussion.

 

[C.Tracy]

Wow, this is GREAT information. I for one can use it since I sweat fluid out just about as fast as I can put it in, and it does not matter what the temperature is sometimes. I like to drink a liter of water before I reach the trailhead, after that I normally go through 3 to 5 liters during the hike depending on its length and difficulty.Thanks for all the information.