How Much Water Do You Need When Working Out?

Chris Freytag by Chris Freytag | June 23rd, 2009 | 2 Comments
topic: Fitness, Health & Wellness


Most of us have memorized this rule: Drink eight 8-ounce glasses of water a day. But did you know that the human body is made up of about 66 percent water? We are more than half water — so staying well hydrated is essential when being active outdoors. But how much water you need, and when you need it, really depends on the length and intensity of your workout.

For example, a casual stroll while chatting with a friend is a very different half hour spent than one of fast, high intensity walking or jogging. And as the mercury rises outdoors, proper hydration is even more important.

Hydration improves endurance

When we exercise, our core body temperature rises, and we start to sweat to help regulate our temperature. In the heat and high humidity, we sweat even more. (Today on my outdoor run, I was dripping like I just got out of the shower). However, if we are dehydrated due to lack of water, our core body temperature stays elevated, and we can’t cool off. You may experience side effects like dizziness, heat stroke and exhaustion. In addition, studies have shown that exercisers who drink fluids may go 33 percent longer than exercisers who don’t drink anything.

The general rule of thumb is to drink 4 to 6 ounces of water for every 15 minutes of exercise. If you plan to exercise for longer than 90 minutes, you may want to consider using a sports drink during and after your workout to replenish your body with the nutrients and electrolytes it needs. Sports drinks like Gatorade are made for when you are “hot and sweaty” and are scientifically formulated mixtures of sugars and electrolytes to help your body perform during and recover from strenuous long workouts. These drinks were not made to wash down your Happy Meal — they were made for athletes in training and serve an important and specific purpose.

Exercise and stay hydrated hands-free

If carrying a water bottle as you exercise is problematic for you, try these options:

  • There are now waist packs that hold a water bottle, as well as your car keys and/or cell phone. This will free up your hands while you are walking. I like to freeze my water bottle for hot days (but don’t try this with a metal bottle). The water stays cold for longer — not to mention the bottle keeps my lower back cool.
  • Try out the Camelbak Hydration System. You can find them at most sports stores or at many sport-related Web sites. I love this option because it offers a constant stream of water as you are exercising. It is very easy to carry on your back and doesn’t bounce around as you are moving. My family even uses them while we are skiing or on long bike rides.
  • Set up your walks and runs on paths where you know there are drinking fountains nearby. Or take some time to research where some drinking fountains are on your current walking course. Often public trails and parks are set up with us walkers and runners in mind, and they have drinking fountains — you just have to find them!

So guzzle your water during warm weather workouts! Use a sports drink if your workout will be strenuous and over 90 minutes. And remember, beverages that contain caffeine, such as colas, coffee and tea, stimulate fluid loss and promote dehydration.

Stay healthy,


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  1. [...] because you are in water, doesn’t mean you can’t get dehydrated. Check my recent post about how much water you need during exercise. You may not feel the sweat, but your body is losing [...]

  2. Another source of water is in our food. Especially in fruits and vegetables. An apple alone is 80-90% water. So another reason to eat our fruit and veggies.

    Dennis Blair | July 29th, 2010 | Comment Permalink

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