How to Calculate Maximum Heart Rate: Fitness Guide
Estimate maximum heart rate with 220 − age and common alternatives, then map percent of MHR into training zones. Use zone math to plan easy, aerobic, and hard sessions — and know when lab or field testing beats formulas.
How to Calculate Maximum Heart Rate
Maximum heart rate (MHR or HRmax) is the highest pulse you can sustain under all-out effort. Coaches use it as a reference so training intensities can be expressed as percentages — for example, "stay near 70% of max" on an endurance day. Population formulas estimate MHR from age; they are convenient, but individual values can differ by well over 10 beats per minute.
This guide covers the classic 220 − age equation, widely cited alternatives, percentage-based training zones, and the limits of formula-based training. It is general fitness education, not a medical clearance or personalized exercise prescription.
The classic formula
\mathrmMHR = 220 - \textage
Example. Age 40:
\mathrmMHR = 220 - 40 = 180 \text bpm
A target at 70% of max:
0.70 × 180 = 126 \text bpm
This formula is easy to remember and still appears in consumer devices. Research has shown large scatter around the prediction for any single person — treat it as a starting estimate.
Alternative age-based equations
Several alternatives try to reduce average error in specific populations. None is perfect for everyone.
Tanaka et al. (commonly cited):
\mathrmMHR = 208 - 0.7 × \textage
Age 40:
\mathrmMHR = 208 - 0.7 × 40 = 208 - 28 = 180 \text bpm
(Same as 220 − age at 40; the lines diverge at other ages.)
Age 20: Tanaka → 208 - 14 = 194; classic → 200. Age 60: Tanaka → 208 - 42 = 166; classic → 160.
Gellish et al. (one published form):
\mathrmMHR = 207 - 0.7 × \textage
Age 40 → 207 - 28 = 179 bpm.
Other variants exist for women-only samples, older adults, or sport-specific cohorts. If your watch brand uses a proprietary curve, it is still an estimate unless you calibrated with a true max effort or lab test.
Side-by-side at selected ages
From MHR to training zones
Zones are bands of intensity as a fraction of MHR. Naming systems differ; a common five-zone sketch:
For estimated MHR = 180 bpm:
\textZone 2 low = 0.60 × 180 = 108, \quad \textZone 2 high = 0.70 × 180 = 126
So Zone 2 ≈ 108–126 bpm on that estimate.
Worked session plan
Athlete age 30 → classic MHR = 190 bpm.
- Easy run (Zone 2): 0.60 × 190 to 0.70 × 190 → 114–133 bpm
- Tempo (Zone 3): 0.70 × 190 to 0.80 × 190 → 133–152 bpm
- Intervals (Zone 4–5 peaks): often 152+ bpm, with recovery in Zone 1–2
Always ramp effort gradually; zone math does not replace perceived exertion, especially in heat, illness, or poor sleep.
Heart-rate reserve (Karvonen) — a related method
Some coaches prefer intensity relative to heart-rate reserve (HRR), which includes resting heart rate (RHR):
\mathrmHRR = \mathrmMHR - \mathrmRHR
\mathrmTarget = \mathrmRHR + p × \mathrmHRR
Where p is the desired intensity fraction (for example 0.7).
Example. MHR 180, RHR 60, 70% HRR:
\mathrmTarget = 60 + 0.7 × (180 - 60) = 60 + 84 = 144 \text bpm
Compare with 70% of MHR alone: 0.7 × 180 = 126 bpm. Karvonen targets sit higher when resting HR is incorporated — know which system your plan uses.
Measuring a better personal MHR
Formulas are population averages. More individualized approaches (only if healthy enough and appropriately supervised):
- Lab test with progressive exercise and ECG / metabolic cart
- Field tests (for example, well-designed hill or track protocols used by coaches)
- Observed max during a recent hard race or time trial (still not always a true physiological maximum)
Stop and seek medical advice if you have cardiovascular risk factors, symptoms, or are new to intense exercise before attempting maximal efforts.
Factors that shift day-to-day heart rate
Even with a fixed MHR estimate, training-zone bpm can be misleading when:
- Heat and humidity raise HR at the same pace
- Dehydration or illness elevates HR
- Caffeine, stress, or poor sleep changes response
- Medications (for example, some beta blockers) blunt HR
- Cardiac drift in long sessions raises HR at steady external workload
Use RPE (rate of perceived exertion), pace, or power alongside HR when conditions change.
Applications
Building an easy aerobic base. Cap most weekly volume in Zones 1–2 so hard days stay hard.
Structuring intervals. Prescribe work bouts near Zone 4–5 with recoveries that actually let HR fall.
Comparing cardio machines. Treadmill vs bike may feel different at the same %MHR because muscle mass and posture differ.
Watch configuration. Entering age (or a tested MHR) changes every zone the device displays — update it when your estimate improves.
Common mistakes
Treating 220 − age as exact. Individual error can be large; zones then shift systematically too high or too low.
Chasing Zone 5 every session. Max-percentage work needs recovery; more is not better.
Ignoring resting HR methods when the plan specifies Karvonen. Mixing %MHR tables with HRR percentages double-counts confusion.
Using chest-strap and wrist optical data interchangeably without checking. Optical sensors lag and struggle in intervals; validate against a strap if zones matter.
Exercising through warning symptoms. Dizziness, chest pain, or unusual shortness of breath are stop-and-evaluate signals — not a zone problem.
Frequently asked questions
Is a higher MHR always fitter? No. MHR is largely age-related and genetic; fitness shows more in resting HR, HR recovery, pace at a given HR, and VO2 max.
Why is my watch max higher than 220 − age? You may have hit a true effort above the formula, or the watch glitched. Formulas under/over-predict often.
Can MHR increase with training? True physiological HRmax usually does not rise much with training; sustainable power/pace at each %HRmax improves.
Should older adults use Tanaka instead of 220 − age? Many prefer equations that decline more slowly with age, but personal testing still beats either formula.
How often should I update zones? After a better MHR estimate, a large fitness change with new field data, or if prescribed HR caps from a clinician change.
Is fat-burning only Zone 2? Fat oxidation contribution is often relatively higher at easier intensities, but total calorie burn and training goals matter more than the myth that fat loss requires only one zone.
Summary
Start with an estimate:
\mathrmMHR ≈ 220 - \textage
or
\mathrmMHR ≈ 208 - 0.7 × \textage
Multiply by zone percentages to set bpm ranges, or use Karvonen if your plan includes resting HR. Prefer field or lab calibration when training precision matters, and keep hard efforts medically appropriate for you.
Estimate max heart rate and zone targets with our Max Heart Rate Calculator.