Frank has just begun running again. he is 18 years old with a resting heart rate of 74 bpm. calculate 50-75% of his maximum heart rate to find his target heart rate zone.

The maximum heart rate is Frank's age-predicted maximum beats per minute.
220 - Age = Maximum Heart Rate 
220-18=202
The heart -rate reserve is obtained with subtract Frank's heart's resting rate from his maximum rate.
202-74=128
The fat-burning range lies between 50 and 75 percent of your heart-rate reserve.
50% of 128 is 64
75% of 128 is 96
So, the target heart zone for Frank is: (128+64 bpm to 128+75)
Frank's heart rate during running that will most efficiently burn fat is 192 to 203 beats per minute

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