It’s important to stay hydrated throughout the day but it’s especially important to replenish your body with fluids after exercise, particularly after periods of intense physical activity or exercise performed in high temperatures. But what’s the best way to hydrate? 

Water might seem like the obvious rehydration choice but there are other options. Patrick Birmingham, MD, Sports Medicine at NorthShore, discusses the pros and cons of some after-exercise rehydration options:

Water
Every system of the human body requires water to function, so when you exercise and lose water by perspiring, you need to replenish what you lost. On average, every individual needs to consume approximately 1.9 liters of water a day but this amount increases when you factor in exercise, especially high-intensity exercise. 
Pros: Unlike some sports drinks and coconut water, there are no calories in water so you won’t undo any of the good accomplished during your workout. After short, moderate workouts, water should be sufficient for rehydration. 
Cons: After intense workouts lasting more than an hour, your body loses not just water but important electrolytes like sodium and potassium, and these electrolytes will need to be replenished too. In this situation, water might not cut it. 

Coconut water
Coconut water is all the rage but is this “natural” source any better than a bottle of water or a sports drink when it comes to rehydration after a workout?
Pros: Depending on the brand, coconut water has fewer calories, less sodium and more potassium than the typical sports drink. Generally, it also has no added colors and only natural flavors (from other juices, for instance). 
Cons: After an intense workout, the most important electrolyte you need to replenish is sodium. Coconut water has less sodium than most sports drinks, which means it might not be able to do the heavy lifting after a particularly intense workout. Some coconut waters are enhanced with extra sodium but that can alter the flavor and make consumption less pleasant.

Sports drinks
Most popular sports drinks provide approximately 13-19 grams of carbohydrates and between 80-120 milligrams of sodium. 
Pros: Sports drinks are made especially to replace the electrolytes you lose during long, arduous workouts, so they should be your go-to source on high-intensity days. The tasty flavors mean you’re likely to consume enough when you need it most. Pediatric rehydration mixtures like Pedialyte are also a great option. They have just the right combination of electrolytes and carbohydrates with less sugar. 
Cons: Many sports drinks have added artificial flavors, colors and unnecessary sugars. Make sure to check for lower-calorie versions so you aren’t undoing all your hard work at the end of your workout.