There seems to be so much confusion around the hydration needs for endurance athletes, with some claiming to only 'obey your thirst', while others push us to overload our systems with water. In addition to this, I was chatting to a friend who is a dietician, and she was telling me that calories in drinks are a leading issue with obesity in the U.S., but endurance athletes are forcing these types of drinks in during almost every session. Confused yet?
Well, the good news is that you are not alone in your confusion around hydration. Let me first make some general points, then move to specifics on how you should approach hydration. Let's first discuss the obesity question. There is little doubt that drinks that contain high amounts of calories are a negative influence on the rising obesity and diabetes issues in youth and adults in the US (and Western World). These include sodas, energy drinks and others sugar-based beverages. If we could only eliminate these from the nation’s diet, we would see a positive change in other eating behaviors, and create a positive influence on our bulging bellies. The key point to understand, as an endurance athlete, is that the rules and needs of athletes in training and competition have little relationship to the general population. As an athlete it is essential that you segment the calories and fluids you take in during and immediately following training (fueling) with the calories and fluids you take in during the rest of your day (nutrition). The appropriate place for you to take in 'sugar-based' fluids is during and immediately following exercise, as they can assist in performance during and recovery from your training. The key is to get the hydration strategy correct.
So what should you take in during exercise? Well, if possible, you will want to get most of your actual calories from 'your pockets'. In others words, you want to avoid caloric-rich drinks even during exercise. The role of the fluids during exercise is for hydration, not calorie replenishment. With this being said, we do want to mimic, as close as possible, the chemistry of the body's 'water', so some calories and electrolytes are helpful. Read more about electrolytes here. We always suggest keeping your bottles full of a solution that is less than 3 or 4% concentration of carbohydrates, and has some sodium included in the solution. These calories and electrolyte are not included for calorie or electrolyte replenishment, rather to maximize absorption of consumed calories. In order to maintain hydration status, and assist in absorption, you should aim to consume 10-15 ml/kg/hour of the noted fluids. This should be consistent for every single hour of exercise.
The final piece is what to do during the day as an athlete. With the amount of training triathletes and endurance athletes complete, the game between workouts is 'restoration of a balanced status'. Rehydration is key. During the day there is no need to add any calories to fluids, and pure water is absolutely fine. I also don't mind hot beverages, such as tea, and these are especially helpful in the afternoons to prevent those afternoon sleepy periods.