You need to take in salts if you're sweating a [link|http://www.ultracycling.com/nutrition/hyponatremia2.html|*lot*] - ~ 1 g of salt per liter of sweat. If you're just out in the sun for an hour, you probably will be better off with water than guzzling a quart of Gatorade because you'll likely end up consuming more calories than you burned. Plain water obviously can't replace lost salt, but apparently the salt balance can be messed up if too much of any drink is injested.

Gatorade was developed to supply calories in addition to electrolytes. In other words, it's had lots of sugar from day one.

[link|http://www.angelfire.com/electronic/ultramentor/gatorade.html|Linky]:

Purely from the hydration science point, Gatorade is far behind in the current race between race and/or recovery sport drinks. It lacks the mineral/electrolyte content to be a race drink, and does not have the proper amounts/proportion of the carbs and proteins to qualify for recovery drink. Deservingly, Gatorade tends to be looked down upon by the endurance athletes.

[...]

To review the hard science read on. Gatorade's electrolyte profile is 12 mg. sodium to 3 mg. potasssium to 2 mg. phosphorus with micro amounts of magnesium and iron, without which the simple sugar-ingredient osmolality would be so high, it would fail crossing the gastric lining without drawing fluids from the body. Calorically, it produces 60.24 kilocalories of 15.20 grams carbohydrates, 94% of which is simple sugar, 14.32 simple sugar grams in each 8 fluid ounces. As an endurance athlete exercising at an aerobic pace rate, you spend 600 to 900 calories per hour, but your liver can replenish only 240 calories back into the energy cycle from the fuels you consume to delay premature fatigue or the bonk. The faster the carbohydrates are absorbed, the faster the liver can reprocess them, meaning that 32 fluid ounces of Gatorade are minimally required to replenish some of the calories spent. As you know, 32 fluid ounces per hour is quite often implicated in dilutional hyponatremia, not to mention the inconvinience and heavy liquid weight of such high fluid intake.

I don't know if his metabolism numbers are right, but they seem reasonable.

I believe the sugar content in Gatorade was chosen to make it more palatable, not because it's an optimum for quick absorption. But [link|http://faculty.washington.edu/crowther/Misc/RBC/QandA3.shtml|this] article has some references that seem to indicate 4-8% sugar is "optimum".

FWIW.

Cheers,
Scott.
(Who's never liked Gatorade either.)