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Fat and how to burn more of it...
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Here's an excerpt from this special report...
According to conventional wisdom, exercise at a moderate intensity
- such as walking or cycling - puts your body in a fat burning zone.
The idea that exercise in the fat burning zone is the best way
to lose fat is based on the fact that your body burns less
fat the harder you exercise.
Many cardiovascular exercise machines have special fat burning
programs, which change the difficulty level of the exercise depending
on your heart rate.
Is exercise in the fat burning zone the best way to lose weight?
Or is there a faster way to shed the fat?
Intensity
Scientists usually describe exercise intensity in terms of your
maximal oxygen consumption.
Maximal oxygen consumption (known as VO2max) is used as an indicator
of your aerobic fitness. VO2 max is the maximum amount of oxygen
in milliliters your body can use each minute per kilogram of body
weight.
The average value for a sedentary American is about 35, while elite
endurance athletes average about 70. In his inspiring book, It's
Not About the Bike, Lance Armstrong describes having a VO2max
of 85!
The harder you exercise, the higher your heart rate. You're also
said to be working at a greater percentage of your VO2max.
When you walk, for example, you're exercising at around 40% of
your VO2max. Turn that walk into a jog, and both your heart rate
and the percentage of your VO2max that you're exercising at will
rise.
As the exercise intensity continues to rise, you burn less fat
and more carbohydrate.
A good example comes from research carried in the European Journal
of Applied Physiology [24]. In the study, ten active men cycled
at either a low-intensity (33% VO2max) or a high-intensity (66%
VO2max) on separate days for 90 and 45 minutes, respectively.
Total calorie expenditure was similar for the two trials. But subjects
burned more fat (42 versus 24 grams) and less carbohydrate (143
versus 189 grams) during the low-intensity compared to the high-intensity
trial.
However, this study only measured the number of fat calories burned
at two levels of exercise intensity.
In an effort to precisely establish the exercise intensity where
you burn the most fat, researchers from the University of Birmingham
examined fat oxidation (when fat is oxidized, it is burned for energy)
across a wide range of exercise intensities [2].
Test subjects started cycling at a low intensity. Every few minutes,
exercise intensity was increased. During the study, scientists took
blood samples, which they later analyzed. This let them establish
the exercise intensity leading to the highest and lowest rate of
fat use.
FATmax is the exercise intensity where the greatest number
of fat calories are being burned for energy.
FATmin is the exercise intensity where the lowest number
of fat calories are being burned for energy.
FATmax zone refers to the range of exercise intensities
where the number of fat calories burned for energy was within
10% of FATmax.
The study, carried in the January 2002 issue of Medicine and
Science in Sports and Exercise, shows that subjects reached
FATmax at roughly 74% of maximum heart rate (64% of VO2max). FATmin
was reached at 92% of maximum heart rate (89% of VO2max), where
the number of fat calories burned for energy was very small.
The FATmax zone, where the number of fat calories burned for energy
was within 10% of FATmax, occurred between 69 and 79% of maximum
heart rate (which corresponds to 55 and 72% of VO2max).
Some people think this means that aerobic exercise at 74% of your
maximum heart rate is the best way to lose fat.
Are they right? Here's the full story...
This special report is also available in the Members-Only
Area. If you're a member, you can click
here to read it. If you're not a member, click
here to learn more about the benefits of joining.
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