It is common knowledge that cardiovascular exercise is an important part of a heart-healthy fitness regimen.  What most people fail to realize when performing cardiovascular exercises that heart rate plays a major role in determining the type and amount of energy that is burned.

Typically, an individual’s heart rate will increase lineally with the work rate of an exercise.  Similar to fuel for an automobile, energy is burned to keep up with the work rate required of an exercise.  Energy comes in different forms from within the body, for example:  protein, fat and carbohydrates.  So, how do you know whether you are burning fat or muscle?

The answer, my friends, can be found within you…actually, in your heart rate.  By measuring and monitoring your heart rate, you can get a pretty good idea of the amount and type of work needed to burn the preferred energy source.

Remember:  Fat burns before muscle (protein).  The normal person will have a fat-burning range of 50%-60% of your heart rate reserve (the area between your resting and max heart rate).  surprisingly, less work is needed to burn fat than to burn muscle.  So if your primary goal is to tone, build muscle and lose fat, you need to figure out what your target heart rate requires and adjust your work rate to match.

“But, how do I know my target heart rate?”  I’m glad you asked!  It’s actually simpler than it looks:  To find your target heart rate range, you first need to know your resting heart rate and max heart rate.

Your resting heart rate is the measurement of the beats per minute (bpm) your heart is normally pumping blood throughout your body.  To measure your resting heart rate the first step is to, well….rest.

Try to sit or do very little to no vigorous activity for about 10-20 minutes or until you feel as if your breathing is slow and steady and you feel pretty relaxed.  You are going to need either a stop-watch or a clock with a second hand within view, a sheet of paper and something to write with.

Once you are relaxed and have your timer set, take your index and middle finger and place it on the edge of your inner wrist, below the thumb on the opposite hand.  You should feel a light “thumping”.  Start your timer or watch the second hand of the clock for 10 seconds while counting the “thumps”.  After counting for the full 10 seconds, write down your number on a sheet of paper.

Since heart rate is measure in beats per minute, we need to multiply this number by 6 since there are 6 sets of 10 seconds in a minute.  The answer is your resting heart rate.

The other measurement needed is max heart rate.  There are a couple ways of finding your max heart rate, but for the purposes of this blog we’ll stick to the simplest form.  Grab that sheet of paper and pen again and subtract your age in years from 220.  That’s it, it is that simple.  The answer is your max heart rate.  This is a general maximum bpm your heart will function at before you either puke or pass out…yuck!

You have your resting heart rate and your maximum heart rate…but now what?  Now to find your heart rate reserve.  This is the area between your resting and maximum heart rate.  Certain points along your heart rate reserve will initiate the burning of different energy sources.  The average target heart rate for burning fat is 50%-75% of your heart rate reserve.

This chart is an example of a person with a resting heart rate of 60 bpm and maximum heart rate of 120 bpm.  The heart rate reserve is a total of 120 bpm, which is the maximum heart rate minus resting heart rate.  In this example, the target heart rate for burning fat would be between 120 bpm (50% heart rate reserve) and 150 bpm (75% heart rate reserve).

Why is this good information to know?  Contrary to popular believe, going hard-core balls-to-the-wall during a workout, may actually be doing more harm than good.   Especially if your main goal is to build muscle and burn fat.  Working at a level higher than Aerobic or Steady State may result in burning muscle mass, thus resulting in the loss of gains.  Anaerobic and Maximal exertions should be used to increase speed and endurance.