Heart Rate Zones: Karvonen vs Maffetone vs Tanaka vs Lactate Threshold

The basic HR numbers

Three numbers underpin every zone system:

• HRmax — the highest heart rate your cardiovascular system can sustainably reach under maximal effort.
• HRrest — your heart rate at complete rest, ideally measured first thing in the morning before stimulants.
• HRR — heart-rate reserve, the difference (HRmax − HRrest).

HRmax is largely genetic and falls with age. Training improves HRrest substantially (a sedentary adult may be at 70 bpm; a well-trained endurance athlete at 40–50 bpm). Training does not raise HRmax in adults.

Method 1: Karvonen (HRR-based)

Published by Karvonen and colleagues in 1957^[1]. The method computes training zones as percentages of HR reserve, then adds HRrest back to get a target HR:

Target HR = HRrest + (intensity_pct × (HRmax − HRrest))

Example:
  HRmax = 190, HRrest = 55, HRR = 135
  60% HRR = 55 + 0.60 × 135 = 136 bpm
  80% HRR = 55 + 0.80 × 135 = 163 bpm

Strengths:

• Incorporates training status via HRrest. A fit runner's 60% HRR is a harder absolute intensity than an untrained person's 60% HRR, but both represent the same relative cardiovascular stress.
• Scales correctly with fitness gains. As HRrest drops, the same percentage HRR moves upward in absolute terms.
• Validated for healthy adults by 70 years of use and replication.

Limits:

• Requires accurate HRmax. A poorly estimated HRmax (e.g. 220 − age) biases every zone.
• HRrest can be skewed by caffeine, poor sleep, or illness. Take HRrest on a quiet morning, average across a week.

Method 2: Percent of HRmax

The simplest approach: zones are fixed percentages of HRmax.

Zone 1 (recovery):        50–60% HRmax
Zone 2 (aerobic base):    60–70% HRmax
Zone 3 (tempo):           70–80% HRmax
Zone 4 (threshold):       80–90% HRmax
Zone 5 (VO2 max):         90–100% HRmax

The CDC and ACSM^[5][6] use variations of this in general-population guidance because it's one step simpler than Karvonen.

Weakness: percent-HRmax zones are not comparable across individuals with different HRrest. A fit runner at 70% HRmax is at a lower relative cardiovascular stress than a beginner at 70% HRmax. For precision training, this is a real problem; for “walk at a moderate pace for 30 min/day,” it's fine.

The Heart Rate Zone Calculator offers both Karvonen and percent-HRmax, side by side, so you can see the spread.

Method 3: Tanaka's HRmax formula

The 220 − age rule is a 20th-century heuristic with a published RMSE of about 10 bpm^[2]. Tanaka, Monahan, and Seals (2001) fitted HRmax across 18,712 subjects and produced:

HRmax = 208 − 0.7 × age

Example ages:
   25 years → HRmax 191 bpm    (220 − age = 195, Tanaka 191)
   40 years → HRmax 180 bpm    (220 − age = 180, close match)
   55 years → HRmax 169 bpm    (220 − age = 165, Tanaka 4 higher)

Tanaka's formula has better fit than 220 − age particularly for adults over 40, where the old rule underestimates. The residual RMSE is still ±7 bpm, which means HR zones built on either age formula are inherently noisy.

For a meaningful training block, a field HRmax test beats any age formula. Protocol: thorough warm-up, followed by three-to-four hard efforts (5 min at progressively higher intensity), with a final all-out 90-second push. The peak HR observed in the final effort is a defensible HRmax.

Method 4: Maffetone (180 − age)

Phil Maffetone's 180 − age formula^[3] is a simple one for building an aerobic base. Start at 180 − age in bpm, then apply adjustments:

Base: 180 − age

Adjustments:
  −10 if major illness / on meds for cardiovascular conditions
  −5  if de-conditioned, frequent illness, allergies
   0  if consistently training injury-free
  +5  if experienced (2+ years) and competing

The resulting number is the upper bound of training HR for the aerobic-base phase. Maffetone's method asks you to stay below this HR for extended base-building periods (weeks to months), then re-test aerobic performance at the cap (pace at MAF HR) to track improvement.

Viewed critically, 180 − age is roughly an LT1 estimator for a healthy recreational athlete. Compared to lab-measured LT1, the formula is plausible for ages 30–50 and a fit individual, and can be 10–15 bpm off for older athletes or deconditioned ones.

The method's weakness is that it treats a single HR cap as the entire aerobic prescription. It doesn't give you zones; it gives you one ceiling. For athletes moving beyond base-building, Karvonen zones or LT-based zones are more useful.

Method 5: Lactate-threshold-anchored zones

The most defensible zone system anchors to LT1 and LT2 (or their equivalents: first and second ventilatory threshold). A laboratory lactate step test, or a validated field test (e.g. 20-minute time-trial for LTHR estimation), gives you two anchor points instead of relying on age formulas.

Zone 1 (recovery):        < 82% LTHR
Zone 2 (aerobic base):    82–89% LTHR
Zone 3 (tempo):           89–94% LTHR
Zone 4 (threshold):       94–100% LTHR
Zone 5 (VO2 max):         > 100% LTHR

For anyone doing structured endurance training — marathon, triathlon, cycling race prep — this is the system to use^[4]. The reference anchor is measured on your physiology, not estimated from a population formula.

Which method to pick

Situation                                        Best method
────────────────────────────────────────────────────────────────────────────────
General fitness, gym cardio                     Percent-HRmax (Tanaka formula)
Recreational runner / cyclist                    Karvonen with field-tested HRmax
Base-building aerobic block                      Maffetone 180 − age cap
Serious endurance training                       LT-anchored zones
Athlete with chest strap + good head for data    LT-anchored, re-tested twice a year

Zone systems in use across sports

Different sports use slightly different zone systems with different numbers of zones and different boundary definitions:

System              Zones    Boundaries                Common in
──────────────────────────────────────────────────────────────────
ACSM 5-zone          5        % HRmax                   General fitness
USAT / tri           5        % LTHR                    Triathlon
Coggan 7-zone        7        % FTP (power-based)       Cycling
Friel 7-zone         7        % LTHR                    Endurance coaching
Seiler 3-zone        3        LT1, LT2                  Polarised endurance research

The 3-zone Seiler model maps cleanly onto Zone 2 / grey zone / Zone 5 and is the mental model underneath polarised-training discussions. The 5-zone model gives you more granularity for prescribing specific workouts. Don't try to translate between systems zone-by-zone; the boundaries don't line up cleanly.

What happens when your HRmax drops

HRmax falls with age — roughly 0.7 bpm per year on the Tanaka model^[2]. Over a decade, that's a 7-bpm shift in your zone boundaries if you don't update the inputs. Most athletes never refresh their HRmax and end up with progressively inflated zone ceilings.

Practical recommendation: refit zones annually. A single field HRmax test per year takes 15 minutes and keeps the zone system honest.

Drift within a session

Cardiac drift is a phenomenon where HR rises at the same workload over the course of a long session due to thermoregulatory strain, dehydration, and glycogen depletion. Over a 90-minute Zone 2 run, HR can drift from 135 bpm at minute 20 to 150 bpm at minute 90 without any increase in actual effort.

Two implications:

• Pace by HR at the start of a session; transition to pace-based targeting in the last third of long sessions if HR has drifted.
• Significant cardiac drift over consistent routes is a fitness marker — less drift indicates better aerobic efficiency.

Autonomic nervous system and HR data

Resting HR isn't a static number; it reflects the balance between sympathetic and parasympathetic autonomic activity. A resting HR that's 10 bpm above your baseline for a few days is a credible signal of accumulated training stress, poor sleep, illness, or psychological stress. The Resting Heart Rate Calculator tracks rolling averages so you can detect these shifts without reading too much into a single morning.

HRV (heart-rate variability) is a related but distinct metric that responds more quickly to training stress than RHR. Wearables that produce daily HRV scores can be useful as a recovery indicator, with caveats: consumer HRV measurements are noisy, and the useful information is trend rather than absolute value.

The HRrest problem

If you rely on Karvonen, your HRrest needs to be accurate. Practical protocol:

• Measure on waking, before moving much, for 60 seconds.
• Average across 5–7 consecutive mornings.
• Re-measure quarterly — resting HR drifts down with aerobic training and up with accumulated stress.

The Resting Heart Rate Calculator (with a 7-day input mode) smooths day-to-day noise and flags if your HRrest has moved significantly.

How Zone 2 fits in

In Karvonen, Zone 2 typically corresponds to 60–70% HRR. In percent-HRmax, it's 65–75% HRmax. In Maffetone, Zone 2 lives at or just below the 180 − age cap. In LT-anchored zones, Zone 2 is 82–89% of LTHR. All four systems roughly agree on where Zone 2 lives; they disagree on where exactly to draw the upper bound. The Zone 2 Heart Rate Calculator computes a conservative Zone 2 upper bound using Karvonen HRR with the Tanaka HRmax formula.

Summary

• Karvonen is the best field method for athletes who know their HRmax and HRrest.
• Tanaka's HRmax formula is less biased than 220 − age.
• Maffetone is a conservative aerobic-cap estimator, useful for base-building, not a full zone system.
• LT-anchored zones are the gold standard for serious endurance work.
• All methods drift with external conditions. RPE is a useful cross-check.

Tools: Heart Rate Zone Calculator, Zone 2 Heart Rate Calculator, Resting Heart Rate Calculator.

Population boundaries of each zone model

Every zone-anchoring formula and framework was developed on a specific population. The published accuracy only applies inside that population; outside it, the error band widens.

• Karvonen 1957 — sample. 6 young men, ages 20–25, healthy, in a longitudinal training study. The HRR-percentage framework emerged from this very small cohort. Subsequent validation work across larger samples has confirmed the general principle but documented individual variation that Karvonen's small sample couldn't detect.
• Tanaka 2001 — sample. Meta-analysis of 351 studies and a laboratory sample of 514 healthy adults, ages 18–81. Tanaka's 208 − 0.7×age formula is the least-biased population estimator available, with an RMSE of ~7 bpm. For competitive endurance athletes, the formula still under-predicts HRmax by 3–8 bpm on average; for very sedentary adults it over-predicts by similar amounts.
• Maffetone 180 − age cap. Not derived from a controlled dataset; originated as a coaching heuristic from Phil Maffetone's clinical observations. The "cap" is deliberately conservative — Maffetone's framing was that most athletes over-train, and a low aerobic ceiling prevents that. There is no peer-reviewed validation of the 180 − age number as representing any specific physiological threshold.
• Lactate threshold (LTHR-anchored) zones. Individualised to the athlete via a specific test (ramp, step, or critical-power protocol). When the LT test is done well, zones are highly accurate for that athlete at that time; when the test is done badly (insufficient duration, wrong substrate state), the zones are garbage. Requires redoing the test when fitness changes meaningfully.
• None of the HR-zone formulas apply to athletes on HR-affecting medication. Beta-blockers, certain thyroid medications, and some anti-anxiety medications alter HR response at exercise. For these athletes, HR zones are invalidated; pace, power, or RPE-based training is the correct substitute.

Alternative-view framing: HR vs power vs pace vs RPE

The honest comparison of intensity-anchoring metrics:

• HR-based zones. Integrate internal load but lag effort, drift with external conditions, and can be invalidated by medication or dehydration. Best for: long steady-state aerobic work where environmental variability is controlled.
• Pace-based zones (running). Precise, externally measured, don't drift with internal state. Blind to external conditions (hills, wind) and require re-calibration as fitness changes. Best for: intervals, race-pace work, time-trials.
• Power-based zones (cycling). Instantaneous work output, insensitive to conditions. Requires a power meter. Gold standard for cycling intensity prescription if the equipment is available.
• RPE-based zones. Most flexible, no equipment required. Accuracy depends on athlete's calibration experience. Works across all modalities and adjusts automatically to daily readiness.

For most athletes, the defensible approach is pairing two of these: HR + RPE for long aerobic work, pace + RPE for intervals, power + HR for cyclists. The pair catches disagreements that signal something off about the training day — elevated HR at planned pace usually means accumulated fatigue or heat stress; higher RPE at planned HR usually means poor sleep or under-eating.

Worked example: zone mismatch diagnosis

A 38-year-old triathlete has four zone systems computed for her training:

Input values
  Tanaka HRmax:   208 − 0.7 × 38 = 181 bpm
  Field-test HRmax: 188 bpm (6 min progressive run)
  HRrest (7-day avg): 48 bpm
  LTHR (ramp-test derived): 167 bpm

Zone 2 upper bound across systems
  Percent-HRmax (75% of 181 Tanaka):         136 bpm
  Percent-HRmax (75% of 188 field-tested):   141 bpm
  Karvonen (70% of HRR at Tanaka HRmax):     141 bpm
  Karvonen (70% of HRR at field HRmax):      146 bpm
  Maffetone (180 − age):                     142 bpm
  LT-anchored (89% of LTHR 167):             149 bpm

Spread: 136 to 149 bpm at the "Zone 2 ceiling" — 13 bpm band

For this athlete, Tanaka-percent-HRmax is the most conservative ceiling; LT-anchored is the most aggressive. The 13-bpm gap represents real physiological uncertainty, not formula bickering. Pacing at 136 bpm produces true Zone 2 aerobic stimulus reliably across days; pacing at 149 bpm pushes into the grey zone on hot days, poor-sleep days, or after a meal. The defensible practical Zone 2 cap for this athlete is 142–145 bpm — near the average of Karvonen and Maffetone — with daily RPE cross-check to catch grey-zone drift.

Common failure modes

• Defaulting to 220 − age. The Tanaka formula's 7-bpm RMSE beats 220 − age in every published comparison. Continuing to use 220 − age in 2026 is a choice, not an oversight.
• LT zones computed from a bad LT test. A ramp test where the athlete didn't reach true LT or didn't use a standardised protocol produces garbage zones. If you're going to use LT-anchored training, commit to doing the test properly or don't bother — bad LT zones are worse than default percent-HRmax zones.
• Using zones computed from a static HRmax for years. HRmax drifts down with age at roughly 0.7 bpm per year; zones anchored on a 10-year-old measurement systematically push the athlete into higher zones than the percentages intended.
• Ignoring cardiac drift in long sessions. Pacing by HR at the 80-minute mark of a 2-hour Zone 2 run with 10 bpm of drift converts the workout into grey-zone work at what looks like Zone 2 HR. Switch to pace-based pacing after the first third of long sessions.
• Treating wrist-optical HR as equivalent to chest-strap HR during intervals. Optical sensors commonly disagree with chest-strap ECG by 8–15 bpm at high intensities. For threshold and VO2-max interval prescription, cross-validate against a chest strap. Wrist-optical is fine for steady-state Zone 2 work.