Dr. Bob Murray Responds
As referenced a couple days ago, I caused a little bit of a stir by saying, in my interview with Dan Wetzel of Yahoo!, that Gatorade didn't show significant performance benefits for the majority of Americans who don't work out for at least one hour. I'm certainly not a doctor, but I've spoken to people who have done research. With that in mind, I thought it would at least be fair to allow Dr. Bob Murray (pictured left) of the Gatorade Sports Science Institute to let him weigh in on this debate, so here goes:
"The broad answer is that the benefits that Gatorade provides are related to the individual's need for water, carbohydrate, and electrolytes. The harder people exercise, the longer they exercise, and the warmer the environment, the greater the benefits they can realize from drinking adequate amounts of Gatorade. In more-sciencey parlance, the greater the water and electrolyte loss in sweat and the higher the carbohydrate oxidation by active muscles, the greater are the differences between Gatorade and water."
"The obvious question then becomes: when do the Gatorade benefits kick in? In one important regard, those benefits start immediately because physically active people voluntarily ingest more Gatorade than water -- and therefore stay better hydrated. As you may recall, this happens for two reasons. The first is that people prefer flavored, sweetened beverages and typically drink more than they do with plain water. In a sense, that's a no-brainer, although the science behind that is actually quite robust. The second is that Gatorade electrolytes maintain the osmotic drive to drink by assuring that the sodium level of the blood is maintained above the thirst threshold for a longer period of time."
"Ingesting water quickly slakes thirst and minimizes drinking because water quickly dilutes blood sodium concentration below the thirst threshold. Better hydration means better preservation of cardiovascular control, starting with better maintenance of blood volume. Even when water is ingested in equal volumes, Gatorade does a better job maintaining blood volume. That's another benefit of the Gatorade electrolytes, principally sodium and chloride. Better blood volume results in lower heart rate and greater blood flow to muscles and skin. Those electrolytes also mean less fluid loss via urine with Gatorade than with water. In brief, staying well hydrated is in and of itself a major performance benefit. Substantial dehydration can occur fairly quickly in many people. For example, 30 minutes of exercise on a warm day can provoke enough sweat loss in some people to result in a level of dehydration that compromises performance. Staying better hydrated with Gatorade is a real benefit when performance is at stake."
"Finally, the carbohydrates in Gatorade provide valuable energy for muscles and for the central nervous system. When exercise is sufficiently vigorous, supplying carbohydrate results in a performance benefit that is in addition to that provoked by staying well hydrated. Interestingly, recent research shows performance benefits during exercise of less than an hour duration and although we're still trying to figure out the mechanism by which those improvements occur, they do exist when the exercise is vigorous enough to put a premium on carbohydrate oxidation. We've always shied away from identifying a specific time at which the performance benefits of Gatorade are manifest because, for example, it's silly to think that an athlete would get no benefit after 59 minutes of exercise and suddenly realize benefits in the 61st minute."
"So here's the punch line: drinking Gatorade improves exercise performance anytime the need for fluid, carbohydrate, and electrolytes is great enough to create an opportunity for improved performance. This can certainly happen in less than 60 minutes and it will be interesting to learn the results from future research as to the lower limits of those circumstances."
