Everyone knows hydration is extremely important, and as the heat index around the country pushes 100, hydration is basically all I can think about. The weather man says to stay inside, but the training must go on, so what should you do?
First of all, how much water should a normal person drink in a day? According to the American Dietetic Association (ADA) the human body is 50 - 75% water, and a person can lose about 2 1/2 liters a day. However, you aren't a normal person! Hot weather or heavy exercise can cause 1 - 2 liters of fluid loss every hour - imagine exercising IN hot weather. The problem with water loss at this level is that it can happen before you start to feel thirsty, so it is up to you to keep up with it.
But how much fluid do you need? According to the American College of Sports Medicine (ACSM) you need to be taking in fluids the whole time leading up to an event - or a workout - and 2 to 3 hrs before you need to drink 2 to 3 cups of water. That's easy, 2 to 3, 2 to 3 beforehand! Then during exercise you should continue to drink 6 to 12 oz every 15 to 20 min. How can we make that easy? I suggest carrying a measuring cup with you on every run. . . Kidding! Actually, you can swallow about one ounce at a time - give or take - so every 15 to 20 minutes you need to stop at a drinking fountain and take at least 6 swallows of water, even if you aren't thirsty. Something worth looking into though is carrying a water bottle with you - not kidding this time -and, there are a lot of options. Different companies like Nathan, Fuel Belt, and Amphipod (as well as others) make products that make carrying water easy. There are hand-held bottles with straps so your hands don't get tired (this is what I use) and also belts that have bottles for water and pouches for other nutrition products. Water will keep you hydrated for up to an hour of exercise, but don't forget to drink after your workout too!
WAIT! You're training for a marathon? And you can't get your Sunday 20 miler done in less than an hour? Don't worry, the ACSM has some recommendations for you too! After an hour, liver and muscle glycogen stores become depleted. Have you heard of the term "hitting the wall?" This is it! What you need is a drink that has 4 to 8 percent carbohydrate - sugar - and also added electrolytes - mainly sodium. This is easy to get in a drink like Powerade or Gatorade, or by drinking water, eating fruit - like an orange or banana - and some pretzels - with salt on the outside. (On that note, don't forget that a lot of the food you eat every day contains water, especially fruits and vegetables - which I know you are all eating anyway!)
Why do these drinks need to contain salt? Actually, there are two real reasons for this. One is that salt continues to make you thirsty, promoting intake of fluids when you may not normally feel like drinking. The other is that water alone can cause abnormally low levels of blood sodium, otherwise known as acute hyponatremia (acute = severe and rapid onset. hypo = not enough. natr = sodium. emia = blood. . . so rapid onset of not enough sodium in your blood.) Your cells need a balance of sodium and potassium, but when you sweat you lose sodium at a higher level, and it needs to be replaced. This condition can be life threatening, mainly because it is often misdiagnosed and mistreated, so be careful!
It might be helpful for you to know the symptoms of dehydration as well as hyponatremia, so I included them here (from MayoClinic.com)
- increased heart rate
- increased respiration / trouble breathing
- decreased sweating
- muscle cramps or weakness
- nausea / vomiting
- loss of consciousness
As you can see the symptoms of hyponatremia closely resemble those of dehydration, so when in doubt you need to take in a drink with electrolytes. Those drinks won't hurt you if you are dehydrated, but downing a lot of water can be a problem if you are experiencing hyponatremia. And if you think you are experiencing either one of these in the extreme, you should go to a doctor for help. Don't let this scare you away from running in the heat though! Now that you are informed you can get your workout in and still feel good the rest of the day, and the next day for your next workout - which we all know is the most important thing!