Purposes of sports drinks:

The ideal oral rehydration beverage:

1. Tastes good to the individual

2. Is absorbed rapidly

3. Causes little or no stomach upset

4. Maintains extracellular fluid volume & fluid absorption rate

5. Enhances exercise performance by maintaing hydration & blood sugar levels

Two main factors effect the performance of sports drinks: intestinal fluid absorption & gastric emptying.

1. Intestinal fluid absorption (how quickly small intestine absorbs fluid & nutrients):

Carbohydrate - low to moderate levels of glucose increase fluid absorption.

Sodium - low moderate levels of increases fluid absorption.

Osmolality - hypotonic to isotonic fluids containing NaCl and glucose increase the rate of fluid absorption.

2. Gastric Emptying (how quickly stomach empties):

Volume - increased volume increases emptying rate.

Calorific content - increased energy content decreases emptying rate.

Osmolality - increased solute concentration decreases emptying rate.

Exercise - intensity exceeding 75% of maximum decreases emptying rate.

pH - large deviations from 7.0 decrease emptying rate.

Hydration level - dehydration decreases gastric emptying and increases risk of gastrointestinal distress.