Heart Rate Zone Calculator
Your Personal Data
Calculation Method
Zone Details
Description:
Active recovery, warm-up, cool-down
Perceived effort:
RPE 1-2
Workouts:
Easy jog, active recovery, warm-up
Description:
Aerobic base, endurance fundamentals
Perceived effort:
RPE 3-4
Workouts:
Long runs, base endurance
Description:
Active endurance, aerobic threshold
Perceived effort:
RPE 5-6
Workouts:
Tempo, marathon pace, fartlek
Description:
Lactate threshold, high intensity
Perceived effort:
RPE 7-8
Workouts:
Threshold intervals, hard tempo
Description:
Maximum aerobic power, very high intensity
Perceived effort:
RPE 9-10
Workouts:
VO2max intervals, short intervals, sprints
Understanding heart rate zones: science at the service of your training
Heart rate zones represent one of the most powerful tools available to endurance athletes. Based on decades of exercise physiology research, they allow you to precisely quantify exercise intensity and optimize every training session. Whether you're a triathlete, trail runner or road runner, understanding and using these zones will transform your approach to training.
The physiological foundations
During physical exertion, your heart adapts its beating rate to meet the oxygen needs of active muscles. This relationship between effort intensity and heart rate was studied as early as the 1950s by Finnish physiologist Martti Karvonen, who developed the heart rate reserve method, still widely used today.
Each intensity zone recruits different energy systems:
- Low zones (1-2): Aerobic metabolism dominates, using mainly fat as fuel. This is the domain of base endurance.
- Intermediate zone (3): Transition to mixed fat/carbohydrate use, corresponding to tempo or marathon pace.
- High zones (4-5): Anaerobic metabolism takes over, with lactic acid production. These zones develop power and the ability to sustain intense efforts.
The different calculation methods
Our calculator offers four scientifically validated methods, each suited to specific needs:
1. Percentage of max HR
The simplest and most accessible method. It uses your maximum heart rate (HRmax) as the only reference. Although less precise than other approaches, it's perfectly suited for beginners or those who don't know their resting HR.
2. Karvonen Method (Heart Rate Reserve)
Developed in 1957, this method incorporates heart rate reserve (HRmax - resting HR) into the calculation. It's considered more accurate because it takes into account your current fitness level. Studies show a better correlation with oxygen consumption (VO2) than with the simple percentage method.
3. Lactate Threshold Zones (LTHR)
Used by professional athletes, this method is based on your lactate threshold heart rate – the maximum intensity you can maintain for 45-60 minutes. LTHR zones, popularized by coaches Joe Friel and Andrew Coggan, offer the best precision for interval training.
4. MAF Method (Maffetone)
Dr Phil Maffetone developed his 180 - age formula to define an optimal aerobic training zone. This approach, adopted by many ultra-trail runners and long-distance endurance athletes, promotes aerobic base development and metabolic efficiency.
The impact of sport on heart rate
An often overlooked aspect is the influence of body position on heart rate. In swimming, the horizontal position and hydrostatic pressure reduce HR by 10 to 15 beats per minute compared to running. Conversely, cycling, with its seated position, can generate slightly higher HRs at equivalent effort.
Optimizing your training with zones
Smart use of zones allows you to structure your training according to the polarization principle: about 80% of volume in zones 1-2 (low intensity), and 20% in zones 4-5 (high intensity), while minimizing time spent in zone 3 (the "gray zone"). This approach, validated by numerous studies on elite athletes, optimizes physiological adaptations while reducing the risk of overtraining.
Zones also allow you to periodize your training: base phases with aerobic dominance (zones 1-2), specific phases with threshold work (zone 4), and competition phases with high intensity work (zone 5).
Limitations and recommendations
Keep in mind that heart rate is influenced by many factors: fatigue, stress, temperature, altitude, hydration, caffeine. Cardiac drift (progressive increase in HR at constant effort) is normal on long efforts. Calculated zones are estimates – listen to your body and adjust if necessary.
For optimal precision, opt for a laboratory stress test to determine your reference values (HRmax, LTHR). Failing that, the Tanaka formula (208 - 0.7 × age) offers the best HRmax estimation according to recent meta-analyses.
Frequently Asked Questions about Heart Rate Zones
The choice depends on your available data and goals:
- % HRmax: Simple and quick, suitable for beginners or if you don't know your resting HR
- Karvonen (Reserve): More accurate as it accounts for your resting HR, recommended for most athletes
- LTHR (Lactate Threshold): Most accurate if you know your lactate threshold (exercise test), used by professionals
- MAF (Maffetone): Ideal for building aerobic base and optimizing fat burning
For a reliable resting HR measurement:
- Measure upon waking, before getting up
- Stay lying down for 2-3 minutes before measuring
- Choose a day after a good night's sleep (not after a party or intense training)
- Repeat the measurement over 5-7 days and calculate the average
A resting HR between 50-60 bpm generally indicates good cardiovascular fitness. Elite endurance athletes can go below 40 bpm.
Body position and environment directly influence heart rate:
- Swimming: Horizontal position reduces venous return and hydrostatic water pressure compresses vessels, lowering HR by 10 to 15 bpm
- Cycling: Seated position with less muscle mass engaged can increase HR by +5 bpm at equivalent effort
- Running: Vertical position with maximum leg engagement → reference values
This is why triathletes should use specific zones for each discipline.
The Karvonen method, developed in 1957 by Finnish physiologist Martti Karvonen, uses heart rate reserve (HRmax - HRrest) to calculate zones.
Formula: Zone = HRrest + (HRmax - HRrest) × % intensity
It's more accurate because:
- It integrates your current fitness level via resting HR
- Studies show a better correlation with VO2 (oxygen consumption) than the simple percentage method
- It accounts for individual variations in physical condition
From most to least accurate:
- Lab exercise test: Most reliable, with medical supervision and VO2max measurement
- Field test: After good warm-up (15-20 min), do 3×3 minutes at maximum intensity with 2 minutes recovery. The peak reached is close to your HRmax
- Estimation formulas:
- Tanaka (recommended):
208 - 0.7 × age - Classic:
220 - age(less accurate) - Gellish:
207 - 0.7 × age
- Tanaka (recommended):
Important: The 220-age formula can underestimate or overestimate your real HRmax by 10-20 bpm. A real test is always preferable.
Polarized training is a scientifically validated approach where intensity distribution follows the 80/20 model:
- 80% of volume in zones 1-2 (low intensity, base endurance)
- 20% of volume in zones 4-5 (high intensity, intervals)
- Minimize time in zone 3 (the less effective "gray zone")
This method, used by elite athletes, optimizes physiological adaptations while reducing risks of overtraining and chronic fatigue.
Many factors can influence your HR at equal effort:
- Fatigue and overtraining: Higher HR at rest and during exercise
- Heat and humidity: +10 to 20 bpm possible in hot weather
- Altitude: Increased HR to compensate for lack of oxygen
- Dehydration: Thicker blood = heart works harder
- Caffeine: Can increase HR by 5-10 bpm
- Stress and lack of sleep: Significant impact on HR
- Cardiac drift: Normal increase of 10-15% on efforts > 1h
Tip: Learn to cross-reference your feelings with your data. Some days, it's better to reduce intensity even if your HR seems "normal".