Client just bought a heart rate monitor and wants to know what zone to be in for fat burning, aerobic base and high-intensity intervals. You need their specific BPM zones before they set up the watch.
Heart Rate Training Zones
Training
Optional — enables Karvonen method
Max HR (Tanaka): 208 − (0.7 × Age)
Karvonen target = RHR + (HRR × Zone%)
HRR = Heart Rate Reserve = Max HR − Resting HRZone 2 (60–70% HRR) is the most important for aerobic base and fat metabolism — often neglected in favour of high-intensity work.
Results are estimates for planning purposes. Verify with current standards and a qualified professional.
1 What this calculator does
Calculates personalised heart rate training zones using the Karvonen (Heart Rate Reserve) method when resting HR is known, or percentage of max HR when it is not. Uses three methods to estimate max HR: standard (220 minus age), Tanaka (2001) and Gelish (2007).
2 Formula & professional reasoning
Max HR estimation:
Standard: 220 - Age
Tanaka (2001): 208 - (0.7 x Age) [most validated]
Gelish (2007): 207 - (0.7 x Age)
Karvonen (Heart Rate Reserve):
HRR = Max HR - Resting HR
Zone HR = Resting HR + (HRR x Zone%)
Percentage of max HR method:
Zone HR = Max HR x Zone%
The Karvonen method produces more personalised zones because it accounts for resting heart rate -- a proxy for cardiovascular fitness. Two people with the same max HR but different resting HRs (50 vs 70 bpm) should train at different absolute BPM targets. The Tanaka formula is the most validated for estimating max HR and avoids the systematic underestimation of the 220 minus age formula for older adults.
3 Worked examples
⚠️ Illustrative example only — not clinical or professional instruction.
Basic
Zone calculation without resting HR
Given: Age: 35 | Method: Tanaka | No resting HR
Working:
Max HR: 208 - (0.7 x 35) = 183.5 -> 184 bpm | Zones as % of max HRAnswer: Zone 1 (50-60%): 92-110 bpm | Zone 2 (60-70%): 110-129 bpm | Zone 3 (70-80%): 129-147 bpm | Zone 4 (80-90%): 147-166 bpm | Zone 5 (90-100%): 166-184 bpm
💡 Without resting HR, percentage of max HR gives approximate zones. Karvonen with resting HR gives better personalisation.
Standard
Karvonen zones with resting HR
Given: Age: 35 | Resting HR: 58 bpm | Method: Tanaka
Working:
Max HR: 184 | HRR: 184 - 58 = 126 | Zone 2: 58 + (126 x 0.60) to 58 + (126 x 0.70) = 134-146 bpmAnswer: Zone 2 (base aerobic): 134-146 bpm | Zone 3: 146-159 bpm | Zone 4: 159-171 bpm
💡 With Karvonen, Zone 2 starts higher (134 bpm) than simple % method (110 bpm). A fit person with RHR 58 has more cardiovascular capacity -- their zones reflect this.
Advanced
Older athlete -- Tanaka vs 220-age
Given: Age: 55 | Resting HR: 52 | Compare methods
Working:
220-age: 165 bpm | Tanaka: 208-(0.7x55) = 169.5 -> 170 bpm | Difference: 5 bpmAnswer: Tanaka gives higher max HR (170 vs 165) for this 55-year-old
💡 The difference grows with age. At age 55, 220-age gives 165; Tanaka gives 170. For older athletes, Tanaka is meaningfully more accurate -- 220-age systematically underestimates max HR in older adults.
4 Sanity check
Five training zone guide
Zone 1 (50-60%): Active recovery | Zone 2 (60-70%): Base aerobic | Zone 3 (70-80%): Aerobic threshold | Zone 4 (80-90%): Anaerobic threshold | Zone 5 (90-100%): VO2 max effort
Fat burning zone context
Zone 2 burns highest fat% but higher zones burn more total calories and more total fat in absolute terms
Fat loss is determined by total calorie deficit -- not the fat-burning percentage during exercise.
Max HR formula accuracy
All max HR formulas have standard deviation of +-10 to 12 bpm
A lab VO2 max test is the only accurate way to determine true maximum heart rate.
Resting HR as fitness indicator
RHR <60: good cardiovascular fitness | RHR <50: excellent | RHR >80: below average fitness
5 Common errors
| Error | Cause | Consequence | Fix |
|---|---|---|---|
| Using 220-age without considering individual variation | Default formula in most devices | Max HR underestimated by 5-10 bpm for adults over 50 -- all zones set too low | Use the Tanaka formula (208 - 0.7 x age) for adults over 40. Better still, conduct a supervised maximal HR field test with an exercise physiologist. |
| Training exclusively in Zone 2 for all goals | Misunderstanding the polarised training model | Insufficient stimulus for VO2 max improvement at higher intensities | Most evidence supports a polarised approach: 70-80% of training in Zone 2, 10-20% in Zone 4-5, and minimal time in Zone 3 (the grey zone). |
| Trusting wristwatch optical HR during high-intensity exercise | Over-relying on wrist-based optical sensors | Zones based on inaccurate data during HIIT or rowing | Wrist-based optical HR sensors are unreliable with significant arm movement. Use a chest strap (Polar, Garmin) for accurate HR during sprint, HIIT or rowing sessions. |
| Not accounting for cardiac drift on long sessions | Treating HR zones as static throughout exercise | Under-estimating intensity on sessions longer than 60 minutes | On long sessions, HR drifts upward 5-15 bpm at the same pace due to dehydration and thermoregulation. Use rate of perceived exertion or power output on sessions over 60 minutes. |
6 Reference & regulatory links
7 Professional workflow
Common tools used alongside this one:
Calorie Burn Estimator
Calorie burn varies significantly by heart rate zone -- estimate burn from specific zone-targeted sessions
→
Rest Period Calculator
High-intensity Zone 4-5 work requires full recovery between intervals -- use Rest Period Calculator for interval rest times
→
TDEE Calculator
Aerobic training volume affects TDEE significantly -- adjust calorie targets based on weekly training load
→