Thursday, February 1, 2007

The Fat-Burning Zone Myth

You've probably heard it, "you have to exercise at a lower intensity to burn more fat.. to get in the "fat-burning zone." guess what, it's a myth!

Here's how it got started. Your body is always "burning" a mixture of carbohydrates and fat for fuel. This mixture tends to contain a little more fat during lower intensity exercise. Somebody took this to mean that a lower intensity workout was best for losing weight.. not so!

1. It all comes from the same "pot". It doesn't matter if you're burning a little more fat or a little more carbohydrate at any particular time in your fuel mix. It all comes from the same calorie pool. The bottom line is, how many calories are you burning.

2. Moderate intensity exercise actually burns more calories in a given time period. For example, you may burn 200 calories during a 30 minute low intensity exercise session and 300 calories during a 30 minute moderate intensity exercise session. Bottom line.. burning more calories is better for weight loss.

3. Moderate intensity exercise increases your basal metabolic rate (BMR) more than lower intensity exercise. This means that you'll burn more calories 24 hours-a-day.

4. Here's the one I like! Moderate intensity exercise gives you a better "high"! You know, the "exercise high" you get when your body releases endorphins and adrenaline. This can really elevate your mood and is great for people who are depressed.

So, how can you know how intense your exercise is? Your heart rate is your body's "speedometer" and an excellent gauge of exercise intensity.

Here's how to calculate your target heart rate range for moderate to high intensity exercise:

The most accurate way to determine what your heart rate range should be while your exercising, is to use the Karvonen equation:

First, determine your theoretical max heart rate (Max HR) by subtracting your age from 220.

Next, determine your resting heart rate (Rest HR) by measuring it first thing in the morning in a seated, resting position.

Then, determine the lower end and upper end of your target heart rate range:
(Max HR - Rest HR) X .50 + Rest HR = lower end
(Max HR - Rest HR) X .80 + Rest HR = upper end

For example, if you are 40 years old with a resting heart rate of 60:

Lower end of range
220 - 40 = 180 (Max HR)
(180 - 60) X .5 + 60 = lower end of range
120 X .5 + 60 = lower end of range
60 + 60 = 120

Upper end of range
220 - 40 = 180 (Max HR)
(180 - 60) X .8 + 60 = upper end of range
120 X .8 + 60 = upper end of range
96 + 60 = 156

So, in this example, your "aerobic training zone" or "target heart rate range" would be 120 to 156 beats per minute. That means that for the majority of your exercise session, your goal should be to maintain your heart rate within that range. If you are just starting your exercise program, you should be at the lower end of the range. As you become more conditioned, you can move up in the range.

This will help you to get the most benefit from the exercise you do.

Get movin'! :)

Note: Be sure to check with your doctor before starting or making changes to your exercise program.


http://www.weightlossarticles.com/art_fatburningzone.html