So often I have seen gym members spend countless hours on the treadmill strolling along waiting for the fat to melt off their bodies.
The belief is if you are in the “fat-burning zone” you are maximizing your fat loss. To get a clear understanding of whether this belief is true or false we must first define the “fat-burning zone” and what the “cardio training zone”.
The fat burning zone is ‘Low Intensity Cardio’ where your heart rate is between 60 – 70% of your maximum heart rate. This heart rate range is reached by standing up, walking fast or jogging. Will you burn fat yes, but just 50% of total calories you consume are coming from fat. If you maintain that intensity level after 20 min 70-80% of calories are coming now from fat and just 20-30% from carbohydrates. But this is the time when most of the people stop anyways.
The cardio training zone is ‘High Intensity Cardio’ and your heart rate is between 70 – 85% of your maximum heart rate.
Maximum heart rate can be estimated by the following formula:
(220 – Age) = Maximum Heart Rate
Example: (220-28) = 192b.p.m. (beats per minute) is the maximum heart rate.
fat burning zone – low intensity zone 192 x 60% – 70% = 115 – 134b.p.m.
cardio training zone – high intensity zone 192 x 70% – 85% = 134 – 163b.p.m.
So is the “fat-burning zone” the best way to lose fat?
You better sit down for this one… the answer is no.
Although the “fat-burning zone” uses a higher percentage of fat for fuel; you need to look at the big picture which is calories burned. Below is a chart that compares the two training zones.
Low Intensity Training burns 50% fat for fuel ex: 100 calories x 50% = 50 calories from fat
High Intensity Training burns 40% fat for fuel ex: 160 calories x 40% = 64 calories from fat
Say, for example, you burn 100 calories in 20 minutes of Low Intensity exercise compared to 160 calories in 10 minutes of High Intensity Exercise, you’ve still burned more total fat doing High Intensity Exercise.
The bottom line:
For individuals new to exercise it is recommended to start in this low intensity zone (60 – 70% of maximum heart rate). There will be some benefit in the first 2-3 weeks, initially they can experience even some weight loss.
But after this initial stage gradually we need to increase the intensity of our routine. Remember, this increase corresponds to a 70 – 85% of Maximum Hart Rate. Maintaining a higher intensity of exercise for a longer time could be sometimes very chalanging. In this cases what is called interval training represents a powerful tool. This means that we can increase the intensity level for a short period of time ( 30sec. – 2 min) returning after each interval to a basic intensity level. For example an initial intensity corresponding to 60% of MHR. First interval at an increase to 80% of MHR, maintaining this level for 1 minute, returning to a 60% MHR for 2-3 minutes. and starting a new cycle