Last week, I addressed how to determine how much to drink during exercise. However, I didn’t discuss what to drink. There are a huge variety of fluid options available from sports drinks to powders and electrolyte tablets that are added to water. It can be confusing to know which product is best for performance. So when do you choose a sports drink instead of an electrolyte beverage or just plain water?

Through sweating, you lose not only water, but also electrolytes like sodium, potassium, magnesium, and calcium. Like sweat rate, sweat composition also differs between athletes. Some athletes are heavy salt sweaters, which can be seen by salty lines on their clothing. Sports drinks and electrolyte tablets can help to replace the electrolytes that are lost in sweat, while water will only replace the water component of sweat. Sports drinks also provide carbohydrates that provide an energy source for performance while electrolyte tablets contain minimal carbohydrates.

In general, if you’re exercising for less than 45 minutes or at an easy intensity, then water will meet your fluid requirements. If you’re exercising for a longer time, intensely or tend to be a “heavy sweater” then you may benefit from a sports drink or water with added electrolytes. Athletes competing in sports with heavy equipment such as football or hockey or those exercising in hot or humid environments may also benefit from a sports drink or electrolyte tablets.

As mentioned above, sports drinks offer carbohydrates, while electrolyte tablets do not. When you’re exercising for longer than an hour, the carbohydrates in a sports drink can benefit your performance by providing additional energy. However, if you’re taking in carbohydrates from other sources such as gels, taking in the extra carbohydrates from sport drinks can cause GI issues. For those athletes competing in stop and go high intensity exercise such as hockey or basketball, there is a performance benefit from just swishing a sports drink in your mouth and then spitting it out. No need to even swallow!

When choosing a sports drink, look for one that provides about 5-8 grams of carbohydrate per 100 mL. It should also contain carbohydrates from a mixture of sources such as glucose, fructose, sucrose, and maltodextrin because this variety improves carbohydrate absorption. Going over the recommended amount of carbohydrates is not a good idea. Too high a carbohydrate content can cause major GI issues, such as diarrhea. This is one reason why fruit juice, pop, and energy drinks are not recommended during exercise. They have almost twice the carbohydrate content as sports drinks, leading to bloating and discomfort.

One of the problems with sports drinks is that many of them don’t contain sufficient sodium to replace sweat losses. In addition, most sports gels tend to contain minimal sodium. Athletes in prolonged endurance events should aim for a sodium consumption of about 250-500 mg/hour. To hit the 500 mg mark you would have to drink just under 5 cups of Gatorade per hour. Electrolyte tablets tend to provide more sodium than sports drinks. One Nuun electrolyte tablet dissolved in 2 cups of water contains 360 mg of sodium. This is a much more realistic fluid intake during exercise. Electrolyte tablets tend to have added magnesium, potassium and calcium. However, the amount of these electrolytes lost in sweat is too minimal to create problems, so their addition isn’t really necessary.

The added electrolytes can also help stimulate thirst and increase water absorption to better help prevent dehydration. Additionally, if you drink just water and are a heavy salt sweater, it could result in a condition called hyponatremia, which is low blood levels of sodium. This is a serious and dangerous condition and could lead to seizure, coma or even death.

Finally, a word about the oh-so popular coconut water that has been promoted as an alternative to sports drinks. Unfortunately, while coconut water might be tasty and refreshing, the electrolyte content is not optimal for hydration during exercise. It contains too little sodium to help replace losses.

Like how much you drink during exercise, what you drink is also individualized. As always, make sure that you practice your hydration strategy in training, well in advance of race day in order to ensure that your plan is both well tolerated and perfected.

I am excited to announce that I am offering a new service of creating individualized carbohydrate loading meal plans based on your unique requirements and lifestyle preferences. I decided to offer this service because most athletes fail to properly carbohydrate load in the days leading up to an endurance event. Yet carbohydrate loading is critical for optimal performance. I am offering this service completely through e-mail, so there is no need to travel and is available to everyone regardless of location. Even if you’re not planning on running a marathon until the fall, I would encourage you to start practicing your carbohydrate loading plan now, so that you can ensure that it’s perfected by race day. E-mail me at for more information.

Categories: Megan Kuikman

Megan Kuikman

Hello! I’m Megan Kuikman. I’m a Registered Dietitian with specialized training in sports nutrition. My goal is to help athletes and active individuals achieve a healthy attitude towards health, training, and food. I empower athletes to fuel properly for training in order to restore their health and enhance performance. You can get in touch with me at:


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