Dr. Craig Dossman (Doc Dossman), is deemed by many as the top sports medicine practitioner in his native Southern California who has worked with a number of athletes such olympic medalist Carmelita Jeter and entertainment mogul, Janet Jackson  shares about how the body uses water vs sports drink for hydration.

I’m sure you’ve heard that you need to drink eight glasses of water a day. Questions start popping up when we move into sports and exercise, though. How much should I drink? What does it mean to “stay hydrated”? Does Gatorade or Powerade really make a difference? What are electrolytes? To answer these questions, we have to go back to the basics.

We’re talking about exercise and fluid replenishment, so let’s get down to the nitty gritty with some facts.

What is exercise and what does it do to our body? Exercise entails that your muscles are using the food we eat and the air we breathe to function. That has two consequences in our body:
1) The energy used by muscles gives off heat.
2) Our body needs to accommodate for this heat.
If our bodies are unable to dissipate the heat, our body temperature can rise. If the temperature rises too much (past 106 and 108 degrees Fahrenheit, or 41-42 degrees Celsius), our tissue cells and especially our brain cells start deteriorating. This is called heatstroke, and can lead to death. In cold temperatures, the environment will sap the heat from our bodies so we don’t need to worry about cooking ourselves to a crisp. In moderate or hot temperatures, our body will produce sweat, and the evaporation of the sweat from our skin dissipates heat from our body. It’s a chain of events.

 

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Why is this a problem?

The more fluid your body loses, the lower your body’s sweat rate is – the sensitivity of your body’s sweating mechanism drops. With this drop in sensitivity, you have just compromised your number one cooling mechanism. Not to mention, studies have shown that body water loss equal to just 1% of your body weight is enough to diminish your ability to perform a set task. I am 220 pounds…I hope I’m not so heavy by the time you read this, but I will be at risk if I lose 2.2 pounds of water. So, fluid replenishment is important because we don’t want to compromise our performance and we definitely don’t want to risk heatstroke and death. Now that we understand why we need fluid replenishment, we can talk about when to have water vs. sports drinks.

The main goal of BOTH water and sports drinks is, like previously discussed, to replenish fluid loss during sweating and to prevent heatstroke. Sports drinks, unlike water, contain carbohydrates in the form of sugars, and other electrolytes such as potassium and sodium. Another important difference is that it is flavoured. Sports nutrition research and clinical studies about fluid intake have been boiled down to two scenarios:

Scenario A, you are an endurance athlete exercising more than 120 minutes at a time.
Scenario B, you are not an endurance athlete and are exercising less than 90 minutes at a time.

In Scenario A, you need to maintain performance for a long time. So, the carbs (sugar) in sports drinks can help DELAY (not prevent) fatigue by maintaining your blood sugar levels. The addition of electrolytes (sodium, potassium) may help your intestines absorb the sugar and fluid more efficiently.

Scenario B, when you exercise for less than 90 minutes at a time, carbohydrates have an insignificant impact on performance simply because your muscles are not working long enough to deplete your body’s original nutrient stores. In fact, it is better to NOT have carbs and electrolytes in your beverage because they slow down the time it takes for your stomach to empty the fluids into the intestines where they are absorbed. Water retention is so unnecessary here, wouldn’t you agree?

 

If you do not like the taste of water, then choosing flavored water or just chilling your beverage can make it taste better.

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I know you want to know how much you should drink during your day rather than just during physical activity. There are so many theories on this topic. The most popular one we hear is drinking half your body weight in ounces. I agree that body-weight is the main factor. I tell my patients to drink 32oz/50lbs of their body-weight. It’s a bit more aggressive but most active people and athletes that I work with have more muscle mass than your average human being. To whom much is given, much is required! Either theory will make great impact. Maybe start small and step up your game when your bladder can hold it. Crawl before you walk!

 

 

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References:
1. Guyton, A. C., & Hall, J. E. (2006). Sports Physiology. Textbook of medical physiology (11th ed., ). Philadelphia: Saunders.
2. Wolinsky, I., Puhl, S. M., & Buskirk, E. R. (1998). Nutrient Beverages for Physical Performance. Nutrition in exercise and sport (3rd ed., ). Boca Raton: CRC Press.
3. Wolinsky, I., & Senay, Jr., L. C. (1998). Water and Electrolytes during Physical Activity. Nutrition in exercise and sport (3rd ed., ). Boca Raton: CRC Press.