Fitness Friday

Heart Rates- Fat Burning Zone vs Cardiovascular Zone

I have seen gym members spend countless hours on the treadmill strolling along, holding on to the treadmill while reading, just waiting for the fat to melt off their bodies. And I'm sure you all have seen the charts on the cardio equipment that show the fat burning or cardio zone.
You think, " Well, I'm here to lose fat so I will stay in the fat burning zone or do the fat burning program."

This is one of the most widely mis-understood principles of fitness. Here is the low-down.

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 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, by this time, most people stop their cardio anyways.

The cardio training zone is ‘High Intensity Cardio’ where 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, they gradually need to increase the intensity of the routine. Remember, this increase corresponds to a 70 – 85% of Maximum Heart Rate. Maintaining a higher intensity of exercise for a longer time can be very challenging and must be worked up to. Interval training represents a powerful tool to achieve this. Interval training is when you increase the intensity level for a short period of time ( 30sec. – 2 min) returning after each interval to a basic intensity level.

For example:
2 min at 60-70% Max Heart Rate(MHR)
1 min at 70-85% MHR
Repeat this cycle for 30-45 minutes

The best way to track your heart rate is to use a heart rate monitor. To learn more about them, go to polarusa.com.

*This formula is not scientific, but it gives you a good guideline of where you should be. If you are looking for a more scientific/tailored number, see a personal trainer to perform a heart rate test.