You don't just lose water when you sweat; you lose electrolytes. When are sports drinks with electrolytes necessary? Nutrition Diva sat down with sports nutritionist Dr. Kelly Pritchett to get some answers.
Are there times when sports drinks with electrolytes are necessary for hydration?
Nutrition Diva listener Phillip writes: "I work hard outside every day and I sweat a lot. I drink 2 to 3 liters of Gatorade Zero for the electrolytes. I choose the artificially-sweetened drinks to avoid consuming too much sugar, but are the artificial sweeteners or other ingredients in these drinks bad for me?"
Phillip brings up several interesting questions: When is it necessary to replace the electrolytes we lose when we perspire? Is a sports drink like Gatorade the best way to do this? And what about the sugar or artificial sweeteners in these drinks? Are they harmful?
To help me sort through all of this, I sat down with sports nutritionist Kelly Pritchett. Dr. Pritchett is an Associate Professor in Nutrition and Exercise Science at Central Washington University. She's worked with elite and collegiate athletes as well as with active individuals, and she's an athlete herself. In today's show, I'll share some of the insights and information that I gleaned from my conversion with Kelly.
What happens when you sweat?
Let's bracket, for a moment, the question about sugar vs. artificial sweeteners and talk first about what happens when we sweat. According to Dr. Pritchett, your body might produce anywhere from half a liter to 3 liters of perspiration per hour. How much you sweat will depend on your level of exertion and the conditions—how hot or humid it is, or both. But it'll also depend on your level of fitness, and how accustomed you are to the environmental conditions.
Depending on how long and hard you're sweating, the loss of fluids could cause you to become dehydrated. And this can be remedied simply by taking in plain water.
You're not only losing water when you sweat. You're also losing electrolytes: sodium, magnesium calcium, potassium, and chloride.
But, of course, you're not only losing water when you sweat. You're also losing electrolytes: sodium, magnesium calcium, potassium, and chloride. Dr. Pritchett points out that you lose far more sodium than anything else. Average sodium losses are 1,000 mg per hour! That's almost a one-half teaspoon of table salt.
Excessive and extended sweating can potentially lead to dangerously low blood sodium levels, a serious condition called hyponatremia. In these situations, drinking too much plain water, without any electrolytes, can actually make the situation worse by further diluting the sodium concentration of the blood.
If you're playing a set of tennis, running a 5K, or out in the garden for a couple of hours, and you're otherwise healthy, you're probably fine drinking plain water. But if you are going to be sweating hard for more than 60-90 minutes, Pritchett says it's a good idea to think about replacing those electrolytes as well.
How to replace electrolytes
One easy way to replace electrolytes is to simply eat something salty—some salted nuts or sunflower seeds, for example. So, in Phillip's case, he might choose to take a break every couple of hours and have a quick snack or a meal, along with plenty of water. A salty snack will quickly replace the sodium he may have lost as well as smaller amounts of other minerals.
For athletes engaged in endurance sports, however, eating may not be feasible. That's where sports drinks might seem to make sense. These sports drinks can help replace the fluids you lose, but they may not provide enough sodium to keep up with losses completely.
One easy way to replace electrolytes is to simply eat something salty—some salted nuts or sunflower seeds, for example.
Regular Gatorade, for example, contains about 450 mg of sodium per liter. If you're losing 1000 mg of sodium per hour, you'd have to drink half a gallon of Gatorade every hour to keep up. Powerade, another popular brand, is even lower, with only 225 mg of sodium per liter.
Dr. Pritchett notes that there are some sports drinks (as well as gels and gums) that are specially formulated for endurance athletes and have a higher concentration of sodium. You can also add a pinch of sea salt to your water bottle or your sports drink, she says, to increase the sodium content. And finally, there are salt and electrolyte replacement tablets that athletes often use to compensate for losses.
How much sodium should you take in during exercise?
According to Pritchett, the amount of salt you lose in an hour of exercise is a lot less than the typical American consumes each day. It probably doesn't need to be replaced.
But if you're working in hot conditions for hour after hour, or engaged in intense and extended exercise, how much sodium per hour should you take in? Pritchett says this can vary significantly from individual to individual.
One liter of fluid and 1,000 mg of sodium per hour of extended heavy sweating is a good rule of thumb.
"I have athletes who are very salty sweaters," she explained. "You can actually see a whitish film on their skin after exercise." So it's not going to be a one-size-fits-all prescription. But, one liter of fluid and 1,000 mg of sodium per hour of extended heavy sweating is a good rule of thumb.
That sodium can come from food, sports drinks, salt tablets, sports gels, salted water, or any combination of those things. (Check the nutrition facts label on any product you choose to see how much sodium they contain.) Remember that your post-workout meal will also go a long way to replenishing those electrolytes.
Are sports drinks with artificial sweeteners better?
Finally, let's return to Phillip's question about sugar vs. artificial sweeteners in sports drinks.
Before they became a popular category of soft drinks, sports drinks were designed to support athletes engaged in extended, strenuous exercise. Endurance athletes who exercise long and hard enough to exhaust their muscle stores of glycogen often rely on sugar-sweetened drinks, gels, or goos as a quick source of ready energy that can be consumed during a workout.
Your muscles generally can store enough energy to power you through about 2 hours of nonstop, high-intensity exercise.
You don't need a shot of sugar to get you through a 60-minute Zumba class, by the way. Your muscles generally can store enough energy to power you through about 2 hours of nonstop, high-intensity exercise. Beyond that, you'll probably need to consume some form of calories to keep your performance from flagging. And obviously, a sugar-free sports drink is going to be pretty useless as a source of energy.
Outside of endurance exercise, sports drinks are simply another source of added sugars. I appreciate Phillip's concern about minimizing his intake of added sugars, but I'm not a big fan of consuming artificially-sweeteners beverages throughout the day. Even though they can help people reduce calories and sugar, there are many other concerns. Various studies have looked at the effects of noncaloric sweeteners on things like insulin levels, appetite regulation, and blood sugar metabolism. So far, the reviews have been mixed, with some studies finding adverse effects and others finding no effect.
There are also concerns about the effect of artificial sweeteners on intestinal bacteria. Artificially-sweetened foods and beverages generally don't offer much in the way of nutrition. For all of these reasons, I usually recommend consuming artificially sweetened foods the same degree of moderation that you'd use for sugar-sweetened foods and beverages. And several liters a day is definitely more than I would consider moderate.
The bottom line on sports drinks with electrolytes
If you're exercising for less than 90 minutes, you probably don't need to worry about replacing electrolytes as you go. You also do not need additional sugar or carbohydrate to fuel your muscles. You can drink water to replace the fluids, and you'll be able to replace the electrolytes at your next meal.
If you're exercising for less than 90 minutes, you probably don't need to worry about replacing electrolytes as you go.
Endurance athletes may lose 2-3 liters of sweat per hour for several hours in a row. A sports drink can help replenish fluids and also supply a source of carbohydrate fuel for muscles. However, a sports drink may not contain enough sodium to replace losses.
Now, let's consider those who work outdoors—everyone from military personnel to landscapers to construction workers to bicycle messengers to tour guides. Your level of exertion may not be quite as intense or sustained as an endurance athlete's. Even so, conditions can be extreme, and you may be outdoors for hours on end. Drink plenty of fluids to stay hydrated. If you're not able to eat at regular intervals, you may wish to supplement with an additional source of salt. A salt tablet or a pinch of salt in your water will be helpful.
If your sport or line of work means that you spend many hours a day sweating, you may want to consult with a dietitian or sports nutritionist. It's a good idea to assess your sweat rate and composition and get an individual prescription for fluid and electrolyte replacement.
And thanks to Phillip for his questions. If you have a question for the show, call the Nutrition Diva listener line at 443-961-6206.
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