Originally Posted by electrik

The hotter it is the more you need to drink. Gatorade has a high osmotic pressure than half gatorade and half water. The higher the osmotic pressure in your stomach the worse you'll feel and stop drinking. If your drink is pure gatorade it can lead you to dehydration or vomiting since the heat outside will drive you to drink more and more. Now that gatorade sits there in your stomach, not emptying or easily digesting, because the concentration of sugars in gatorade are too high for the rate you need to consume liquids at to remain active. HEED apparently allows you to drink more calories since the maltodextrin in it doesn't increase the stomach pressure at the same rate as a drink with simple sugars like sucrose.