Heart Rate Training Zones Calculator Formula

Understand the math behind the heart rate training zones calculator. Each variable explained with a worked example.

Formulas Used

Zone 1 Recovery (50%)

zone1_low = round(hrr * 0.50 + resting_hr)

Zone 2 Aerobic (60%)

zone2_low = round(hrr * 0.60 + resting_hr)

Zone 3 Tempo (70%)

zone3_low = round(hrr * 0.70 + resting_hr)

Zone 4 Threshold (80%)

zone4_low = round(hrr * 0.80 + resting_hr)

Zone 5 Maximum (90%)

zone5_low = round(hrr * 0.90 + resting_hr)

Max Heart Rate

max_heart_rate = max_hr

Variables

VariableDescriptionDefault
ageAge(years)30
resting_hrResting Heart Rate(bpm)60
max_hrDerived value= 220 - agecalculated
hrrDerived value= max_hr - resting_hrcalculated

How It Works

Heart Rate Zones (Karvonen Method)

Target HR = (Max HR - Resting HR) x Intensity% + Resting HR

Five Training Zones

| Zone | Intensity | Purpose | |---|---|---| | 1 | 50-60% | Recovery, warm-up | | 2 | 60-70% | Base aerobic fitness | | 3 | 70-80% | Tempo, lactate threshold | | 4 | 80-90% | Anaerobic capacity | | 5 | 90-100% | Maximal effort, sprints |

Worked Example

A 30-year-old with a resting HR of 60 bpm.

age = 30resting_hr = 60
  1. 01Max HR = 220 - 30 = 190
  2. 02HRR = 190 - 60 = 130
  3. 03Zone 2 low = 130 x 0.60 + 60 = 138 bpm
  4. 04Zone 4 low = 130 x 0.80 + 60 = 164 bpm