Hydration During Sports

This article originally appeared on Ultiworld on August 23, 2018.

Staying properly hydrated is key to a successful practice or tournament, no matter what the weather’s like outside. We’ve all had that teammate who cramps late in the afternoon on day two, exclaiming with confusion “but I’ve been drinking Gatorade all weekend!” There’s a lot of conflicting information out there about how to best stay hydrated, often thrown at us from sports drink companies trying to push their product.

Every player has their own unique standby hydration strategy, from pre-mixed Gatorade to powders; coconut water to Nuun tablets; and Pedialyte to plain water. There are some fanatic pickle brine enthusiasts out there, as well. Some folks say to dilute your sports drinks, others say add more salt to it.

Amongst all these different ideas and advertising campaigns, what does the science say?[1]The fundamental science behind hydration has to do with how our digestive system processes water, sugar, and electrolytes in concert with each other. There are two principles at work here: diffusion … Continue reading

Most sports drinks and powders have poor concentrations of sugars and electrolytes, or even use sugars that are hard to digest and can cause an upset stomach. Even plain water misses the mark, since we don’t absorb it as effectively on its own.

Let’s look at the different hydration strategies and how these principles apply when we drink each beverage. In this discussion, I will refer to the bloodstream as being inside your body and the digestive system as being outside your body. So we’re picking up the path of whatever you’re drinking after it’s hit your stomach. If you’re into molecular biology and ultimate, check the footnotes for more science easter eggs.

Plain Water

If you drank pure, distilled water (something I’ve seen teammates erroneously pick up at the store), the complete lack of electrolytes or sugars in the drink would mean that water, sugars, electrolytes, and other dissolved substances would leave your bloodstream and enter your digestive system. One would think that water would, conversely, just absorb across the intestinal wall due to osmosis. The most efficient way for water to enter the bloodstream, however, is following the path of absorbed sodium moving from cell to cell away from the intestinal wall and in toward the bloodstream as local concentrations change. Eventually, we do indeed absorb pure water through osmosis, but it can take a little extra time.

What does this all mean? That sloshing feeling you get when you chug a glass of water is the real, sometimes painful effect of a lack of absorption. Additionally, if you solely drink pure water without taking on any source of sodium, whether in your water or through food, you run the risk of dangerously lowering the concentration of sodium in your body.

Pickle Brine and Low-Calorie Sports Drinks

When a player goes down with a cramp, it seems the first response is to help stretch that muscle and the second is invariably to shout in a panic, “Someone grab the pickle juice!” Depending on the particular recipe of pickles you’re using, this strategy might not help all that much.

As sodium is transported across the layers of cells between the inside of the intestines and our bloodstream, water molecules chase the shifting concentrations of those solutes. However, one of the major entry points for sodium to cross our cell membranes is through a protein that only allows sodium to pass through when paired with a glucose molecule (also known as dextrose), a specific type of sugar.

Many pickle recipes have extremely low concentrations of sugar, if any, or have corn syrup in them. Corn syrup is quite high in fructose, which does not absorb through the same channels as glucose, and therefore does not assist with the transport of sodium into the bloodstream. It takes the right kind of sugar, then, to help gain all the benefits from a beverage, which you’ll rarely find it in pickle juice and won’t find in a low-calorie sports drink that uses artificial sweeteners.

Coconut Water

A few years ago, there was a massive coconut water craze sweeping the sidelines at tournaments. The biggest buzzword getting tossed around was that it’s “isotonic”. That would mean there’s the same concentration of solutes in coconut water as in our blood stream, so the theory went you’d absorb the whole thing easier.

Unfortunately, the balance of those solutes is just as important as their total amount.[2]And coconut water isn’t actually isotonic to blood. We need both sodium and potassium for our cells to function, and specifically, we need a higher proportion of sodium to potassium. Unlike pickle juice, coconut water does have the sugars in it to move into our bloodstream alongside sodium, but an insufficient amount of sodium to accomplish the task and truly replenish what you’re losing through sweat.

Gatorade, Powerade, Pedialyte, and Nuun

In recent years, Gatorade has made the switch from using high fructose corn syrup (HFCS) over to a sugar and dextrose (glucose) blend. This gives Gatorade a definitive edge over Powerade, whose HFCS formulation makes it much more difficult to absorb the electrolytes in the drink. In their current formulations, Gatorade, Pedialyte, Nuun, and coconut water all have the right component pieces in them to potentially be hydrating, but the proportion of all these is extremely important.

The Institute of Medicine has set out a few ranges that are helpful for evaluating sports drinks. The targets for what kind of beverage to drink during prolonged activity in hot weather are 460-490 mg/L of sodium, 78-195 mg/L of potassium, and 5-10% carbohydrate concentration.[3]Additionally, if you want to efficiently absorb the water in the beverages, the total concentration of solutes in the water (including electrolytes, sugar, and any other additives like coloring or … Continue reading The ideal range to help water enter our bloodstream more readily is around 200-250 mmol/L.

At first glance, Gatorade looks like it hits the nail on the head with its amounts—it’s got the right amount of sodium, potassium, and carbohydrates; and claims to be isotonic. Independent testing, however, shows that with all the other additives taken into account, Gatorade actually is pretty solidly hypertonic, on the scale of ~350 mmol/L. A total concentration that high can lead to gastrointestinal distress and simply watering down the Gatorade will drive the portions of electrolytes and carbohydrates down below the ideal range.

Pedialyte is much more rehydrating with respect to water, but the proportion of sodium and potassium is set to be appropriate for recovering electrolytes lost from diarrhea rather than through sweat. The sodium and sugar portions are about half what they need to be, while the potassium runs on the high end of the range.

Finally, Nuun hits an appropriate concentration to effectively rehydrate during exercise by sacrificing on sugar content. While the proportions of sodium, potassium and total solutes when mixed according to directions are appropriate for exercise, the carbohydrate concentration for the tablets that actually contain sugar is down near 2-3%, much like Pedialyte and some coconut water. Sugar-based Nuun (look for sugar or dextrose on the ingredients list) might be an appropriate choice for a shorter workout or with careful attention to getting those missing carbohydrates from food.

Make Your Own

The simple fact of the matter is that many of these beverages are modified from the ideal for hydration and replenishing your electrolytes to serve their actual purpose, like Pedialyte, or to appeal to consumers through better taste or flashy colors.

What’s my recommendation? I’ve personally fallen in love with a homemade electrolyte mix recipe given to me by Aimee Gallo of Vibrance Nutrition. She came in to Strive & Uplift to give a talk on nutrition and this drink recipe has been a lifesaver at some of the muggy tournaments I’ve slogged through since then.

Watch the excerpt on hydration from the Nutrition for the Ultimate Athlete Clinic below to hear her take on hydrating while you play. For the full talk and other clinics designed for ultimate players, check out our memberships for ultimate players.

Aimee’s Recipe

Here’s the recipe she supplied:

There are plenty of other homemade hydration recipes out there, including ones with peppermint tea to supply the potassium, which sounds delightfully refreshing, if a bit clumsy to produce on the sideline.

In a market flooded with hundreds of different electrolyte mixes of ever-increasing prices, the most effective solution may very well be the old-fashioned homemade route. Who knows, maybe one day, it’ll be standard for tournament directors to provide us with chilled peppermint tea instead of straight water. Until then, I’ll keep bringing around my ziploc baggie with bottles of maple syrup, lime juice, and a salt shaker.

References

References
1 The fundamental science behind hydration has to do with how our digestive system processes water, sugar, and electrolytes in concert with each other. There are two principles at work here: diffusion and osmosis. Diffusion is the idea that, given a barrier the molecule in question can cross, a particular type of molecule will move across that barrier until the concentration of that molecule is equal on both sides. Osmosis is that same idea, just applied to the movement of water, specifically. With osmosis, water moves to balance out the total solute, or dissolved molecule, concentration.
2 And coconut water isn’t actually isotonic to blood.
3 Additionally, if you want to efficiently absorb the water in the beverages, the total concentration of solutes in the water (including electrolytes, sugar, and any other additives like coloring or flavors) should be slightly hypotonic to our blood.