With the recent heat wave that has engulfed the eastern seaboard, I thought it would be a good idea to bring up the sports drink/electrolyte issue. Now, most people have heard the phrase “you must drink fluids” repeated over and over; well duh, who doesn’t drink when it’s hot. However, I want this post to provide some laymen terms background and science behind why you need to use sports drinks, when it is best to use them and what is the best type.
Sports drinks – how quickly are they absorbed?
To begin, I think it is important to note that the critical factor in hydration is how rapidly fluids can be absorbed into the blood stream. The absorption of fluids into the body is largely dependent upon the composition of the fluids in terms of its carbohydrate (sugar), sodium (salt) and potassium concentrations. As a general rule, the higher the carbohydrate content, the slower the absorption rate. Thus, your choice of sports beverage would depend on whether your primary aim was rehydration or the replenishment of energy (sugar or fuel) and electrolyte stores.
When is re-hydrating the most important factor
Before and during exercise, re-hydration should be your main priority in order to maintain fluid balance, especially in the hot and humid summer months. Therefore, your best bet would be a sports drink diluted with water. Because of the high sugar content of most sports drinks, the fluid is not readily absorbed into the blood stream. By mixing half water and half sports drink, you provide your body with the best combination of electrolyte replacement and immediate absorption. Products are also available that contain pure electrolyte concentrations that you simply add to water. One of the best brands I know of, and used by many of the elite athletes I coach, is Nuun.
What about re-hydration after a workout
However, after you are finished working out, water or a diluted sports drink isn’t the best choice for your recovery needs. Water and diluted drinks do not contain enough of the sugars and electrolytes that your body needs in order to bring itself back into balance. In addition, because water or highly diluted drinks are so rapidly absorbed, consuming high quantities results in a rise in plasma volume (in non technical terms, this means your body is now over saturated with water or diluted). This rapid absorption leads to a further imbalance of electrolytes and frequent bathroom stops, which will only increase fluid loss and decrease your desire to drink.
Your best bet post workout is a drink that contains a fair amount of sugars and electrolytes that will speed your recovery process and stay with you a little longer. In addition, after you feel hydrated and are finished sweating through your running clothes, you should start to begin your post run recovery fueling (<– members-only article for now, sorry).
I hope this article put an interesting twist on your summer hydration plans and gave you a better understanding of the differences between water and sports drinks. Let us know what questions you might have!