There are a lot of hydration (aka “sport”) drinks out there, ranging from the common Gatorade to esoteric ones like Gleukos. All make claims around why they are the best thing around and why all the other drinks suck.
So, I thought I’d write a bit about my understanding of what makes a good drink and help you decode some of the labels out there.
The first thing that you need from a hydration drink is a sufficient calorie density. Most experts suggest 250 calories perhaps up to 350 calories per hour. So, you need a drink that has that many calories when mixed with a sufficient amount of liquid to make a reasonable dent in your hydration needs (sometimes you may need more or less water). That puts carbs in the 6% to 8% range. Drinks with fewer carbs don’t provide enough energy, and those with more don’t provide enough water.
Gastric Emptying & absorption
Once you have the sugar solution in your stomach, you need to get it absorbed into the bloodstream. The absorption of the water in the hydration drink is increased both by the presence of the sugar (within reason) and by the presence of electrolytes. Fructose is a bit different than other sugars in this respect – see later in the post for more info.
Sweetness is a primary factor in whether you drink enough to meet your energy and hydration needs. There are two important points here:
A sweetness that tastes good at rest is likely too sweet for a workout beverage, so you won’t drink enough of it…
The second point is the most important one. Sucrose (table sugar) is arbitrarily given a value of 100 on the sweetness scale. The good hydration drink makers use different sugars to give you a product that isn’t too sweet but still packs enough carbs.
Acclerade is primarly sweetened with sucrose but uses Trehalose (sweetness=45) to tone the sweetness down, and also a bit of citric acid to make it more sour.
Perpetuem is at the other end of the spectrum, using Maltodextrin, which doesn’t have much sweetness at all, and to be frank, has a bit of a weird taste to it.
There is some good research around the benefits of adding protein to hydration drinks. Accelerade claims that their 4:1 ratio (using whey protein) is the best, Hammer claims that their 7:1 ratio (using soy protein) is the best.
I like the protein, but it does make water bottles a bit messy. I soak mine full of water overnight to make them easier to clean, but you should still make sure never to put the lid on a dry bottle, lest it mold.
Electrolytes are added to hydration drinks to speed their absorption. They also can replace the electrolytes lost to sweat but aren’t usually present in amounts that will replace all the lost electrolytes, so you may need to supplement.
Simple or Complex carbs?
There is a lot of marketing out there on the advantages of complex carbs or glucose polymers over simpler sugars. I’m somewhat skeptical of the claims of benefits (other than their lack of sweetness) – maltodextrin is (for example) rapidly broken down into dextrose.
If you ride for long periods – say, more than 3 hours – it’s not unlikely to find yourself unable to stomach another swig of your drink. This is known as “food fatigue”, and is a good argument for a variety of foods rather than a single one.
Water by itself is bad for a few reasons.
Most obviously, water doesn’t have any caloric value, so it doesn’t help towards your energy needs. But there is a more important reason…
When you are sweating, your body is trying to maintain both your blood volume and the sodium concentration in your blood. If your blood volume goes down, you get thirsty, but if you drink plain water, that ends up diluting the sodium concentration in your blood, and your thirst is turned off.
Not to mention the fact that water is absorbed less quickly by itself, which may lead to a waterlogged (ie “sloshy”) feeling.
Now, if you’re using gels, solid food, or a concentrated drink, then when you add water, you get a good mixture, so that’s okay.
Fructose in drinks
Pre-mixed “original” Gatorade and powerade are both sweetened with high fructose corn syrup. Fructose is a bit of a weird sugar that has a couple of disadvantages:
First, it has a different absorption mechanism that limits how much you can absorb over time. If you get more than the amount that can be absorbed, the rest will be unabsorbed in your digestive tract, which can lead to the dreaded “GI difficulties” (typically diarrhea). Some people have fructose malabsorption which may make this worse.
Second, fructose gets processed through the liver, and is useful primarily in replacing liver glycogen rather than muscle glycogen.
In hydration drinks, the sweetness of fructose is also a severe disadvantage, and premixed gatorade is quite sweet but low on calorie density.
So, fructose is a bad choice as a primary sweetener, but not a problem as a secondary ingredient.
Powdered Gatorade does not have fructose, and their “endurance” formula is a combination of sucrose, glucose, and fructose, so those are likely better choices.
Fruit juice has (no surprise) a lot of fructose in it, and tends to be very sweet.