To calculate the maximum heart rate, you can use the formula:
Maximum Heart Rate = 220 - age
So, if you are 12 years old, your maximum heart rate would be:
Maximum Heart Rate = 220 - 12 = 208
To find your lower range or target heart rate zone, you need to calculate 70% and 85% of your maximum heart rate:
Lower Range = 70% of Maximum Heart Rate
Lower Range = 0.70 * 208 = 145.6 (rounded to 146)
Upper Limit = 85% of Maximum Heart Rate
Upper Limit = 0.85 * 208 = 176.8 (rounded to 177)
Therefore, your lower range or target heart zone would be 146 beats per minute, and your upper limit would be 177 beats per minute.