Introduction
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efficient. According to fitness experts, exercise is more effective
when you work out in a specific heart rate range or zone. This
is referred to as your Target Heart Rate Zone (THRZ) and is
reflected by the number of heart beats per minute. This zone
can vary greatly depending on your age, fitness level and
various other factors. If your heart rate is too low during
exercise, your body reaps little or 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, become fatigued or even run
the risk of injury.
Monitoring exercise intensity helps you to 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 (THRZ) will allow you to
work at the right level of exercise to accomplish this.
1.2.4. How do I determine my Target Heart Rate Zone?
Your THRZ represents the minimum and maximum number of
times your heart should beat in one minute of exercise. The
ACSM recommends that all individuals should work within a
Target Heart Rate Zone of 60% to 85% of Maximum Heart
Rate. This means that your heart rate during exercise should
not fall below 60% or rise above 85% of your maximum heart
rate. Let’s look at John from our earlier example. John is 35
years old, so his estimated maximum heart rate is 220 minus
35, or 185 beats per minute (bpm). The ACSM
recommendation is that John should exercise between 60%
and 85% of 185 beats per minute to stay in his THRZ. Let’s
determine John’s THRZ:
• John’s estimated maximum heart rate: 185 bpm
• Lower target limit: 185 (MHR) X 0.6 111 bpm
• Upper target limit: 185 (MHR) X 0.85 157 bpm
• John’s target heart rate zone: 111-157 bpm
111-157 beats per minute is the range or zone for John’s heart
rate during exercise in order to achieve his goals. If John is a
beginning exerciser, he’ll want to stay at the low end of his
