Wednesday, August 10, 2011

Do you like to drink?

If I had a dollar for every client that said, "I probably don't drink as much as I should", I would have hired someone else to blog for me by now! Whether it's before, during, or after a workout, many athletes struggle with staying hydrated properly throughout the day. Last week I talked about the huge variety of water bottles and belts available to help you stay hydrated during your workout. So lets continue on that theme and this week discuss what type of fluid and how much to put in that lovely bottle or belt that you all bought last week. Remember, the goal of drinking during exercise is to prevent excessive dehydration, which is losing more than 2% of your body weight during a workout.

Gatorade or water? G2 or Powerade Zero? Electrolyte tabs? Glycerol? The choices are plenty...

Gatorade or water?
Which you use depends on what type of workout you're doing. If the workout will be greater than an hour or a very intense workout (such as intervals or hill repeats) lasting at least 30 minutes, using a sports drink (i.e. Gatorade, Powerade, Lucozade, etc.) is the better idea. At this level of intensity or length of workout, you will start depleting your body's glycogen (stored energy, which comes mainly from carbohydrate) and will be loosing significant electrolytes (mainly sodium) in your sweat. Remember that electrolytes in a sports drink actually help your body hold on to the water in the drink. They also play a role muscle contraction and may help prevent muscle cramping.

G2 or Powerade Zero?
Many sports drink companies make specialty drinks such as G2, Powerade Zero, and Gatorade Endurance. These each have a specific purpose. G2 is low calorie; it contains half the amount of carbohydrate as regular Gatorade or Powerade. This is a great choice for kids, adults involved in a lower intensity workout, or adults concerned about their carbohydrate intake. Powerade Zero - as implied by the name - has absolutely no energy (calories), but still provides electrolyte supplementation. It is a good choice for kids or adults doing very low intensity exercise in intense heat. Either of these products may also be a good choice for those trying to lose weight. Gatorade Endurance has the same nutritional make-up as regular Gatorade, but it provides double the amount of electrolytes. If you are a heavy sweater, this is your product! How do you know if you sweat heavily? If your shirt is drenched when others' are slightly damp or when you see white salty stains around the neckline of your shirt, chances are you would be labeled a heavy sweater. Those prone to cramping may also benefit from this product.

Electrolyte tab or Glycerol?
Electrolyte tabs have grown in popularity over the last few years. Athletes often add them to Gatorade or water during training and races to help stay hydrated or to prevent cramping. Add them to Gatorade and you've got a version of Gatorade Endurance; add them to water and you've got a version of Powerade Zero. Not an exact science, but you get the idea. Electrolyte tabs can be a great tool, but how many you use and how often is best determined by consulting with a sports dietitian. Glycerol is often taken by athletes trying to over-hydrate themselves for a race. While in theory it could work, this technique has some pretty uncomfortable digestive side effects and has not shown to improve performance.

But how much?
Once you choose your fluid, next you need to figure out how much of it you should be drinking. Fluid needs during exercise are ~6-12 ounces (~1-1.5 cups) every 15 minutes. There is a range because of the difference in sweat rates among athletes. Gender, body size, body composition, environment, clothing, genetics, sport, and position all affect sweat rate. American football players can lose up to 2 L of fluid per hour during summer training! As you can see, this makes it difficult to provide a blanket recommendation, but starting with 6-12 ounces every 15 minutes will likely get you in the ballpark.

Carbohydrate needs during exercise are ~60 gm per hour after the first hour of exercise. All that carbohydrate does not HAVE to come from fluid, but athletes often just use a sports drink because it is the easiest and best tolerated option. Again, 60 gm per hour is just a guideline, so consulting with a sports dietitian for your individual needs is the best advice.

So grab that water bottle or belt, pick a fluid, and have a great workout!

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