(220 - 14) X .80

To calculate \( (220 - 14) \times 0.80 \):

1. First, subtract 14 from 220: \[ 220 - 14 = 206 \]

2. Then, multiply the result by 0.80: \[ 206 \times 0.80 = 164.8 \]

So, \( (220 - 14) \times 0.80 = 164.8 \).

To understand how you arrived at the Target Heart Rate Range (THRR) of 124 to 165 beats per minute (bpm) based on a percentage of your Maximum Heart Rate (MHR), let's break down the calculations:

1. Determine MHR:

   • The formula for estimating Maximum Heart Rate is \( MHR = 220 - \text{age} \). If 124 to 165 is your THRR, we can calculate MHR using the given percentages.

2. Calculate MHR from THRR:

   • If we denote MHR as \( x \):
     • 60% of MHR: \[ 0.60 \times x = 124 \] \[ x = \frac{124}{0.60} \approx 206.67 \]
     • 80% of MHR: \[ 0.80 \times x = 165 \] \[ x = \frac{165}{0.80} \approx 206.25 \]

3. Approximate MHR:

   • Both calculations suggest that your MHR is around 206 bpm.

4. Find Age:

   • Using the MHR formula: \[ 220 - \text{age} = 206 \] \[ \text{age} = 220 - 206 = 14 \]

This means that if you are 14 years old, your MHR is indeed estimated to be around 206 bpm. Your target heart rate range during exercise, calculated as 60% to 80% of MHR, would then be accurately expressed as 124 to 165 bpm.

Ensure to adjust for individual fitness levels, and consult with a healthcare or fitness professional for personalized recommendations.