If you are 13 years old, which math problem would give you your maximum heart rate? Response area If you are 13 years old, what is your maximum heart rate?Response area After finding your maximum heart rate, remember your target heart rate zone is 70-85% of you maximum heart rate. What would be the lower range or your target heart zone? Response area What would be the upper limit?

To find your maximum heart rate at age 13, you can use the formula: Maximum Heart Rate = 220 - age.

Maximum Heart Rate = 220 - 13 = 207 beats per minute.

To find the lower range of your target heart rate zone, you would multiply your maximum heart rate by 0.70:
Lower range = 207 x 0.70 = 145 beats per minute.

To find the upper limit of your target heart rate zone, you would multiply your maximum heart rate by 0.85:
Upper limit = 207 x 0.85 = 176 beats per minute.

So, the lower range of your target heart rate zone would be 145 beats per minute and the upper limit would be 176 beats per minute.