In this section we will look at a few basic concepts of Heart Rate Monitoring so you can better understand how it
works and how to maximize its use to allow you to reach the fitness level you desire.
Exercise intensity is simply a measure of how hard you are working at a given time during exercise. The American
College of Sports Medicine (ACSM), the world’s leading medical and scientific authority on sports medicine and
fitness, recommends that every individual involved in an exercise program know how hard his/her body is working
during exercise.
Your heart provides the key information for determining how intensely you are working during exercise. Your heart
rate (how may times your heart beats per minute) is really an efficiency rating for your entire body. The number of
times your heart beats during each minute of exercise is a measurement of the intensity of the exercise. If your heart
rate is low, exercise intensity is low; if your heart rate is high, exercise intensity is high.
Maximum Heart Rate (MHR) is the maximum attainable heart rate your body can reach before total exhaustion. True
MHR is measured during a fatigue or “stress” test. This test must be done in a clinical setting and is not practical
or accessible for most people. Fortunately, your MHR can be established with a high degree of accuracy using the
following formula:
Formula 220 - Age = MHR
Example: If John is 35 years old, what is his estimated MHR? 220 - 35 = 185
WARNING:
The use of this formula assumes no underlying heart or respiratory disease or other conditions,
which could be adversely affected by exercise. Consult your doctor before using this formula!
Your heart is the most important muscle in your body and, like all muscles, must be exercised regularly to remain
strong and efficient. According to fitness experts, exercise is more effective when you work out in a specific heart
rate range. This is referred to as your Target Heart Rate Zone (THRZ) and is reflected by your heart rate. This zone
can vary depending on your age, fitness level, and various other factors. If your heart rate is too low during exercise,
your body reaps little to no benefit. This means you’re not likely to see the results you want, like weight loss or
increased endurance. If your heart rate is too high during exercise, you may tire too quickly and become frustrated,
or even run the risk of injury. In this case you are likely to quit exercising because it’s simply too difficult.
Monitoring exercise intensity helps you stay at a level of exercise that allows you to accomplish your goals. In fact,
the ACSM recommends that, in order to get the most benefit from your cardiovascular exercise, you should work
within your THRZ for at least 20 to 60 minutes per workout, 3 to 5 times per week. Knowing your exercise intensity
allows you to work at the right level of exercise to accomplish this.
Your THRZ represents the minimum and maximum number of times your heart should beat in one minute of
exercise. Let’s look at John from our example above. John is 35 years old, his estimated MHR is 185 beats per
minute (bpm). We calculate the THRZ to be +/- 7 bpm of your target heart rate, which is about 75% of your MHR.
132 - 146 beats per minute is the range or zone John will want to keep his heart rate in during exercise in order to
achieve his goals. If John is a beginner exerciser he’ll want to stay at the low end of his THRZ. If John is a more
advanced exerciser he may want to work at the higher end of his THRZ to challenge himself more.
What is Exercise Intensity?
What is Maximum Heart Rate?
Why should I monitor exercise intensity?
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How do I determine my Target Heart Rate Zone?
John’s Estimated Maximum Heart Rate
=
185 bpm
John’s Target Heart Rate (MHR x 0.75)
=
138.74 bpm
~139 bpm
Lower Target Limit (THR - 7)
=
131.75 bpm
~132 bpm
Upper Target Limit (THR +7)
=
145.75 bpm
~146 bpm
John’s Target Heart Rate Zone
=
132 bpm - 146 bpm
Heart Rate Monitoring
