The whole sports beverage category, and hydration as a concept beyond just drinking water, was invented with the initial formulation of Gatorade. The familiar story is that the glucose and salt mixture was invented to help football players at the University of Florida—known as the Gators—cope with the heat during practice.
Energy/hydration synergy
The glucose in the formula helped both in glycogen replenishment in the muscles and in the rapid transport of water from the GI tract. That dual action has been at the heart of energy/hydration formulas ever since, with good reason, said exercise physiologist Susan Kleiner, PhD.
“Simple biology will tell us the be better fueled you are the more hydrated you are. For everyone molecule of glycogen stored in your muscles you have three molecules of water. Using a beverage with a carbohydrate source means you get the water to where you need it, in your muscles,” she said.
In addition to consuming energy via glucose metabolism, heavy exercise can result in the loss of large amounts of sodium via sweat. Low sodium levels can lead to cramping, impaired cognitive performance and ultimately death. The initial Gatorade formulation included salt to counteract that, but Kleiner said it had an added benefit.
“I always laugh when people talk about Gatorade as a thirst quencher. What the salt really does is stimulate thirst and enhance the body’s ability to retain water. If you are doing a short event you don’t really need the electrolytes but you can benefit from the stimulus to drink,” she said.
Kleiner, who works with a number of athlete clients, has come to rely on a fractionated starch called Vitargo whose proprietary technology means the molecule can enter the muscles as fuel (and also transport water with it) faster than competing carbohydrates.
“Under most circumstances a drink made with Vitargo is the most successful drink I’ve used with clients. I got involved with it because of the data I saw that the company had. The biggest thing that athletes struggle with when it comes to fully fueling their bodies is the discomfort they have when they are fully fueled. So that leads them to take in only about 30 grams of carbs an hour, which is not enough. With most drinks you have some GI discomfort. We know that with Vitargo it leaves the GI tract very fast and very few of my clients report GI discomfort,” she said.
Dipeptide hydration aid
Another ingredient that has data behind it in the hydration field is Sustamine, supplied by Kyowa Hakko.The ingredient is a dipeptide consisting of two amino acids, L-alanine and L-glutamine connected by a peptide bond, which functions as a more stable and efficient form of glutamine. The dipeptide form supports electrolyte and water absorption. According to the company, a 2012 study showed improved rehydration with Sustamine helped basketball field goal shooting as compared to no fluid or water alone Another 2012 human study comparing glutamine to Sustamine, showed that Sustamine is absorbed up to 224% better than L-glutamine. Statistically significant increases in both peak and total plasma concentration levels indicated superior absorption, the study showed.
Other ingredients
Creatine, which forms part of the cellular energy pathway, also has some data behind in for its ability to support hydration, Kleiner said.
“Kids studying in a training camp in Texas the kids who were using creatine were better hydrated than the kids who were not,” she said.
Another ingredient that has been used to boost hydration is glycerol. This faintly sweet polyol when taken in solution has been shown to help athletes ‘hyperhydrate’ before events, in other words to load more water into their bodies than they otherwise could. A 1999 paper showed the glycerol hyperhydration boosted cycling time trial performance in hot, humid weather. But a subsequent study conducted 2003 found no benefit over water for a 1-hour test. The equivocal data combined with the fact that glycerol can be tricky to use means it has never really caught on in a big way, Kleiner said.
“It does enhance hydration; it will usher more fluid into the cell. But it is not something everyone would want to use or should use. In the wrong person it can have some negative consequences like a rise in blood pressure,” she said.