Back in your youth sports days, the most pressing question you likely had about sports drinks was which flavor is best. (Shoutout to my Cool Blue crew).

As you got older and started prioritizing both your calorie intake and bank account, your sports drink concerns likely shifted to: When is a sports drink worth it, and when is plain old water still a perfectly fine option?

"The primary purpose of a sports drink is to help improve your physical performance by benefitting your hydration status and energy levels during exercise," says Emma Willingham, clinical dietitian at Houston Methodist. "But, not every workout requires a sports drink. And people who are trying to control the amount of sugar they consume — such as those who are prediabetic or diabetic — may want to be cautious about drinking sports drinks."

How do sports drinks work?

The primary ingredient of a sports drink is water. And we all know how important it is to get plenty of water — especially while exercising or if it's hot outside.

But we also know that the whole point of sports drinks is that they're more than just water.

"There's a whole science to how the ingredients found in sports drinks help improve performance. In addition to water, sports drinks contain electrolytes and carbohydrates — both of which become important when you're sweating a lot or need to quickly refill your energy stores," says Willingham.

Why electrolytes are important

When we sweat, we don't just lose water — we lose electrolytes.

"Among their other important roles, electrolytes are essential for maintaining optimal water balance. They help move water where it needs to be inside your body," says Willingham.

When your electrolytes are out of balance, it becomes harder to maintain proper hydration — leading to impairments in how well your body is able to cool down, regulate blood flow, create energy, prevent cramps and lubricate your joints.

"In addition, as our heart rate increases in an effort to work harder to pump blood to working tissues and muscles, fatigue and shortness of breath can develop," explains Willingham.

Replenishing lost electrolytes by sipping on a sports drink can help prevent these performance impairments from occurring.

Simple carbs are a rapid source of energy

The second benefit of a sports drink is the simple carbohydrates it contains, which can help to quickly refill your energy stores, maintain your blood sugar and delay fatigue.

"Sports drinks tend to get a bad rap because of the sugars they contain. But, when used correctly, this is a very functional type of sugar that can help improve physical performance — especially during longer duration or outdoor exercise," says Willingham.

For instance, some major brands of sports drinks incorporate multiple types of simple sugar, each of which enters your cells using a different receptor. This means these sugars can be taken up and turned into energy much more efficiently — quickly giving you the boost you need to finish your workout.

When is a sports drink better than water?

There are a few circumstances in which your body might benefit from more than just water.

"As a general rule of thumb, if you're exercising longer than an hour — and especially if your workout is outdoors on a hot, humid day — it's time to think about a sports drink," recommends Willingham.

For instance, if you're sweating a lot, sipping on a sports drink isn't just a way to take in water, it's a way to replenish your electrolytes so you can be sure your body is able to effectively use that water.

"Another time a sports drink becomes beneficial is when you need to top off your energy stores during a longer workout," adds Willingham.

Additionally, endurance athletes, such as marathon runners, may consider sipping on a sports drink as a better tolerated way to help maintain blood sugar and energy levels on long runs.

Lastly, sweaty, outdoor workouts aside, Willingham says that sports drinks can also provide benefit when you're sick.

"If you lose significant amounts of bodily fluid while ill, whether due to vomiting or diarrhea, sipping on a sports drink with ice can help quickly replenish lost water and electrolytes," adds Willingham.

Can sports drinks replace water?

In short, no.

"Sipping on a sports drink can be beneficial in the situations above, but that doesn't mean the majority of your hydration needs to include added sugar and electrolytes," says Willingham.

If you're exercising for less than an hour, Willingham says its fine to skip the sports drink altogether and simply opt for sipping on water as you feel thirsty.

"Sports drinks are meant to improve exercise performance and physiology, but they're not a healthy replacement for the water you drink throughout the day," adds Willingham.

Although sports drinks are primarily water, they also contain sugar — an added source of calories — and don't contain any of the nutrients needed to support your overall health, such as fiber and protein.

If you do find yourself opting for sports drinks when you're not exercising or when you're sick, Willingham points out that there are zero-calorie and low-sugar alternatives that can help you rehydrate and/or replenish electrolytes without the added calories from sugar.

"Zero-calorie/low-sugar sports drinks are also a great alternative for individuals who are prediabetic or diabetic and need to avoid the blood sugar spikes that full-sugar sports drinks can cause," adds Willingham.

On the flipside, however, the fast-digesting carbs found in a sports drink could benefit a person who is diabetic and looking for a way to treat low blood sugar.

Additionally, Willingham points out that your diet can help you prepare for losing electrolytes or replenish electrolytes.

If you know you're going to be sweating a lot, consider adding the following to your pre-workout meal:

• Lightly salted foods, like nuts, pretzels and trail mix
• Potassium-rich foods, such as bananas and dark leafy greens
• Sources of magnesium and calcium, including peanut butter, seeds, milk and yogurt