Ping Huang (2:06)

I'm Ping Huang.

Regina Barber (2:07)

You're listening to Shortwave, the science podcast from npr.

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Regina Barber (3:26)

Okay, so electrolytes, we've established we need them, but where do we get them if not a sports drink, right?

Ping Huang (3:32)

I mean, marketing is telling us that sports drinks are an essential source of electrolytes, right?

Regina Barber (3:37)

Oh, yes.

Ping Huang (3:38)

But the simple answer, Gina, like you said, is that you get them from eating a basic, somewhat balanced diet. Fruits and vegetables contain magnes, potassium phosphate. Meat and dairy products contain calcium. And if you're eating these things, you're getting more than enough electrolytes you need to function like. A 20 ounce bottle of Gatorade contains 80 milligrams of potassium. Powerade boasts that it has 50% more electrolytes than Gatorade. But Gina, a medium sized banana has more than 400 milligrams of potassium, which is 400% more than a bottle of Gatorade. Bananas just don't come with the labels.

Regina Barber (4:14)

Boasting that, I mean, I wish they would. I would eat more bananas.

Ping Huang (4:18)

Right. And in fact, most people get plenty of electrolytes through their food. Like sodium, that's the one you lose most in your sweat.

Regina Barber (4:25)

Which makes me wonder, can you like, overdose on these electrolytes?

Ping Huang (4:29)

Not very easily.

Regina Barber (4:30)

Okay, good.

Ping Huang (4:30)

I mean, I spoke with Tamara Hugh Butler, she goes by Tammy, and she's a sports scientist who's now retired from Wayne State University. Her main takeaway with sports drinks is will it hurt you? No. Will it help you?

Regina Barber (4:42)

No. No.

Ping Huang (4:43)

It's not gonna like make you exercise better or increase your performance or make you recover faster. So let's just parse the first part of that. Will it hurt you? No.

Regina Barber (4:54)

Good.

Ping Huang (4:54)

So Tammy says that if you get extra electrolytes, generally speaking, your body will just pee them out. I mean, there's some exceptions.

Regina Barber (5:01)

Yeah, like, I mean, I've had too much sodium and it might have caused bloating, I think.

Ping Huang (5:07)

Yeah, exactly. So that is one effect of sodium. And also if you get too much sodium, in the long term, it can contribute to blood pressure, serious conditions like kidney disease and heart failure. But on the day to day, the body is designed to handle fluctuations in electrolytes.

Regina Barber (5:23)

Yeah, how does the body handle that?

Ping Huang (5:25)

Okay, so Tammy told me that hormones play a big role here. So with sodium, for instance, if you've lost a lot of salt, there's a hormone in your body that will go up telling your kidneys to shed some sodium back into your bloodstream. But if you have too much sodium, like if you just ate a bunch of pretzels and chips, that hormone will go down and the channels that reabsorb sodium close off. So all that extra sodium you just ate that your body doesn't need, it gets flushed out in your urine.

Regina Barber (5:51)

This is really cool.

Ping Huang (5:52)

It's really fascinating, right? And our body regulates other electrolytes, too. So Tammy also said that in our bones, in addition to storing calcium, we also store minerals like more sodium, and also magnesium, which helps regulate your muscles, nerves, blood sugar, and phosphate, which helps build your teeth and bones. So, again, too, we do also have a storage of these minerals that can turn into electrolytes that are held within our skeleton that can be liberated in times of need. What? These can also get unlocked by hormones when our body notices that it's running low on them.

Regina Barber (6:28)

Okay, so we have plenty of electrolytes from, like, the foods we eat for the most part. Can sports drinks actually be helpful, though, to anyone?

Ping Huang (6:36)

Sure. I mean, they are convenient, and they can be useful for people who are sweating a lot. So that includes.

Regina Barber (6:42)

I use them, right?

Ping Huang (6:43)

Yeah, exactly. You know, if you're out there sweating a lot, if you are doing endurance sports, if you're running, cycling, playing soccer for a long time, if you are a laborer that's working outside, that's because what we are sweating out is mostly water and salt, along with additional electrolytes. Potassium, magnesium, and also small quantities of other things like glucose, ethanol, and hormones. A rule of thumb from a sports dietitian I spoke with is that sports drinks can be useful for those who are active for more than an hour. Others told me it's even more like many hours before you might really need to start replenishing those electrolytes. And I also wanted to say they are really useful for people who are seriously medically dehydrated. Asher Rosinger, director of the Water Health and Nutrition Lab at Penn State, told me that a simple packet of sugar, salt, and potassium mixed into clean water has been a lifesaver.

Asher Rosinger (7:35)

ORs, or oral rehydration salts were one of the biggest achievements in public health to treat and deal with diarrheal diseases, which have saved millions of lives around the world.

Ping Huang (7:46)

He researches water issues globally and he says these have been especially helpful for kids in places with poor water access who get sick from diarrhea and then get really sick from dehydration. But that's not the situation that most people in the US Are facing when they grab a sports drink.

Regina Barber (8:01)

Okay, so a person can be both, like, dehydrated and short on electrolytes, and it takes. But. But it takes a lot to get there.

Ping Huang (8:09)

Exactly. Yeah. And being dehydrated in the sense of not having enough water is also different from having a shortage of electrolytes, though they can be related. You know, if you're losing lot of electrolytes rapidly through your sweat, or if you're sick and losing a lot of liquids in other ways.

Regina Barber (8:24)

Yes.

Ping Huang (8:25)

And even so, sports drinks are just one way you can get some of those electrolytes back. You know, milk soup. Asher says that these kinds of liquids can be even more hydrating than sports drinks, depending on what's in them.

Regina Barber (8:37)

Yeah.

Ping Huang (8:38)

But in most cases, if you are dehydrated, you can just drink water and your body will adjust the rest of the.

Regina Barber (8:44)

That's wonderful for me to hear because, like, I love drinking green tea, which is basically water, and I have a cup next to me all day, every day, basically.

Ping Huang (8:52)

Amazing. I love that for you right here. I also love tea, and I'm also obsessed with hydration. You know, I'm the friend who's telling everyone to drink water all the time. I'm telling my mom constantly to drink more water. But here is something else that I also learned that I also found very interesting. So Asher told me that human bodies can actually power through periods of dehydration, that we can perform well for a while, even if we're at a water deficit.

Asher Rosinger (9:19)

It's called voluntary dehydration, where you're able to go, you know, 8, 10, 12 hours without rehydrating to the level you necessarily need to, and then you're able to rehydrate later.

Ping Huang (9:33)

He says that that adaptation was important in human evolution because it made it possible for people to go hunt and forage all day without having to super close to a water source. He also says that our body's hydration level is in flux, like all day long.

Asher Rosinger (9:49)

So as you consume water or food, you become slightly more hydrated. And as you go for a run or you go about your day, you're respirating, you're losing water. So you can think of it as the sinusidal wave of your body kind of adapting to your water inputs and your Water outputs.

Ping Huang (10:10)

And if you are dehydrated, your body's going to tell you, you, you'll get cranky. Your body will complain. You might feel thirsty, get a headache. You might feel kind of out of it. You might even feel your heartbeat a little faster if you're going up the stairs. And if you ignore those signs and don't hydrate, you could get in real trouble.

Regina Barber (10:28)

Yeah. I think the moral of the story here is like, listen to your body.

Ping Huang (10:31)

Right, Exactly. I mean, we're losing water all the time through breathing, coughing, me talking to you, you know, just regular sweating all kinds of ways. So if you're losing a lot of water, just put some more in. And, you know, like we've been emphasizing, it doesn't have to be just drinking water. You can get water and electrolytes from fruits and vegetables, smoothies, soups.

Regina Barber (10:53)

Soups, the big one, soups.

Ping Huang (10:54)

Yeah, soups are delicious. I love soup. And you can also get them from sports drinks. You know, everyone that I talked to when I was reporting the story said, if you like how they taste, go ahead and drink them. It's not going to hurt you to have a few servings a day, at least from an electrolyte standpoint, but also for most people, in most cases, it's not going to help you any more than drinking, drinking water.

Regina Barber (11:17)

Thank you. Thank you, Ping, for bringing us this story.

Ping Huang (11:19)

You're welcome.

Regina Barber (11:22)

All right, shore waivers. If you liked this episode, consider following us on the NPR app or whatever podcast platform you're listening to this on. That way you'll never miss another episode. And if you have a science question, let us know. Our email is shortwavepr.org this episode was produced by Rachel Carlson and edited by showrunner Rebecca Ramirez, Tyler Jones and Ping Huang. Check the facts. Kwesi Lee was the audio engineer. Bette Zunavan is our senior director. And Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Short Wave, the science podcast from npr.

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