Heart Rate Zones for Running: Understand, Calculate, Apply

You've probably heard about heart rate zones before. But between zone 1, zone 5, maximum heart rate, the Karvonen method, and the famous polarized training model, it's easy to get lost. This guide cuts through the noise with concrete numbers and real-world examples.

Training by zones means moving beyond running "by feel" and precisely targeting the physiological adaptations you want to develop: fundamental endurance, lactate threshold, VO2max / MAS… Each zone trains your body differently, and most runners spend too much time in the mediocre middle zones — not easy enough to recover, not intense enough to truly progress.

Why Train by Heart Rate Zones?

Heart rate is the most accessible reflection of your effort intensity. Unlike pace (km/h or min/km), it accounts for heat, fatigue, elevation gain, and your current fitness level. It is an internal indicator of effort — what your body is actually experiencing.

Training by zones allows you to:

• Optimise physiological adaptations: each zone targets different mechanisms (mitochondria, capillarisation, lactate threshold, maximal aerobic power)
• Avoid overtraining: the majority of running injuries happen to runners who train too hard too often
• Structure a coherent plan: intelligently alternate hard and easy sessions
• Track your progress: a lower HR at the same pace is a concrete sign of improvement

Step 1 — Know Your Maximum Heart Rate (Max HR)

What Is Max HR?

Maximum heart rate is the highest number of beats per minute your heart can produce during intense effort. It is genetically determined and decreases slightly with age (~1 bpm per year from age 20). Training does not increase it — but it allows you to perform better at any given HR.

Calculation Formulas

Historical formula (avoid this one): Max HR = 220 - age
Simple, but with a standard deviation of ±10-12 bpm. On a population level, it is unreliable.

Tanaka formula (recommended): Max HR = 208 - (0.7 × age)
Validated on a large study (2001), more accurate for trained adults.

Gellish formula: Max HR = 207 - (0.7 × age)
Very close to Tanaka, slightly more conservative.

Note: these formulas provide estimates. Your true max HR may differ by 10 to 15 bpm. For maximum accuracy, perform a field test.

The Field Test to Measure Your Max HR

The field test is the most reliable method, provided you are in good health and have no cardiac contraindications.

Simplified protocol:

1. 15-minute warm-up in zone 1-2
2. 3 minutes at 10 km race pace (hard, but sustainable)
3. 2 minutes at 5 km race pace (very hard)
4. 1 minute all-out — final sprint
5. The maximum value displayed on your watch is your measured max HR

Medical note: if you are over 40, returning to sport after a long break, or have a history of cardiovascular issues, consult a doctor before performing a maximal effort test. Caution is essential.

Step 2 — Measure Your Resting Heart Rate (Resting HR)

Resting HR is the number of beats per minute your heart produces at complete rest. It is measured in the morning, lying down, before getting up.

How to measure it:

• Take your pulse manually (fingers on the carotid or radial artery, count for 60 seconds)
• Or wear your heart rate monitor overnight

Reference values:

Resting HR decreases with endurance training — it is one of the most reliable markers of your cardiovascular fitness. If your resting HR rises by 5-7 bpm over several days, it is often a sign of fatigue or an oncoming illness.

Step 3 — Choose Your Zone Calculation Method

There are two main approaches.

Method 1: Percentage of Max HR (the simplest)

Zones are calculated as a direct percentage of your max HR. Simple, but it does not account for your resting HR.

Method 2: Karvonen — Heart Rate Reserve (the most precise)

The Karvonen method uses heart rate reserve (HRR = Max HR - Resting HR). It is more personalised because it integrates your current fitness level.

Formula:

Target HR = Resting HR + (% desired × HRR)
HRR = Max HR - Resting HR

Concrete example — 40-year-old runner, max HR 178 bpm, resting HR 52 bpm:

• HRR = 178 - 52 = 126 bpm
• Zone 2 (60-70%): 52 + (0.60 × 126) = 128 bpm to 52 + (0.70 × 126) = 140 bpm

The Karvonen method produces slightly higher zones than the simple percentage of max HR, especially for well-trained runners with a low resting HR.

The 5 Heart Rate Zones: Full Description

Heart rate zones are generally divided into 5 levels, ranging from the lightest to the most intense effort. Some systems use 3, 6, or 7 zones, but the 5-zone model is the most widely used standard in running.

Zone 1 — Active Recovery (50-60% Max HR)

Target HR example (Max HR 180): 90 to 108 bpm
Perceived effort: very easy, you can hold a full conversation without effort

What happens in your body:

• Activation of aerobic metabolism at very low intensity
• Promotes elimination of metabolic waste (lactate) after a hard session
• Maintains blood flow to muscles without stressing them

Used for:

• Active recovery between hard sessions
• Warm-up and cool-down
• Easy jog the day after a race

Common mistake: underestimating these sessions. Zone 1 creates no additional fatigue but accelerates recovery. It is often neglected by ambitious runners who want to "optimise every session".

Zone 2 — Fundamental Endurance (60-70% Max HR)

Target HR example (Max HR 180): 108 to 126 bpm
Perceived effort: comfortable effort, you talk easily but feel like you're running

What happens in your body:

• Preferential use of fat as fuel (lipolysis)
• Development of mitochondria and muscular capillarisation
• Improvement of stroke volume (cardiac output)
• Long-term aerobic base building

Why it's the most important zone:
Zone 2 is the foundation of all endurance progress. Kenyan and Ethiopian runners, among the best in the world, perform 80 to 85% of their volume in zone 2. It allows you to train often, for long durations, without accumulating excessive fatigue.

To learn more about the physiological adaptations of fundamental endurance, read our dedicated article: Fundamental Endurance: the complete guide.

Used for:

• Long weekend runs
• Weekly base volume
• Recovery between intense blocks

Zone 3 — Moderate Aerobic (70-80% Max HR)

Target HR example (Max HR 180): 126 to 144 bpm
Perceived effort: noticeable effort, short sentences when talking, slightly forced breathing

What happens in your body:

• Mix between fat and carbohydrate metabolism
• Onset of significant blood lactate increase
• Moderate cardiovascular stress

The zone 3 trap:
Zone 3 is nicknamed the "grey zone" or "no man's land" of training. It is too intense to allow real recovery and too easy to trigger the powerful adaptations of zones 4-5. Amateur runners often spend too much time here, thinking they are "training hard" while accumulating fatigue without gaining the maximum benefits.

Used sparingly for:

• Lower-threshold runs (moderate tempo)
• Transition phases within sessions

Zone 4 — Anaerobic Threshold (80-90% Max HR)

Target HR example (Max HR 180): 144 to 162 bpm
Perceived effort: hard effort, speaking is difficult, forced breathing, burning sensation in the legs

What happens in your body:

• Significant lactate production: you are approaching the lactate threshold (or anaerobic threshold)
• At the threshold, lactate production equals its elimination — this is the maximum intensity sustainable for 20-60 minutes
• Above zone 4, lactate accumulates and forces you to slow down

Why it's crucial:
Pushing your lactate threshold means running faster for longer before suffering. This is the training zone that most directly improves your race pace over 10 km, half-marathon, and marathon.

Used for:

• Tempo runs (20-40 min at threshold pace)
• Long intervals (3-5 min at 10 km pace)
• Threshold sets: 4 × 8 min with 2 min recovery

Zone 5 — VO2max / MAS (90-100% Max HR)

Target HR example (Max HR 180): 162 to 180 bpm
Perceived effort: maximal or near-maximal effort, impossible to speak, intense breathlessness

What happens in your body:

• Activation of MAS (Maximal Aerobic Speed) — the speed at which you consume maximum oxygen
• Massive recruitment of fast-twitch fibres
• High lactate production, significant oxygen debt

Mind the duration:
Zone 5 cannot be sustained for more than a few minutes. Zone 5 sessions are short, intense, and require sufficient recovery (48-72 hours). Overdoing them leads to overtraining.

For everything you need to know about VO2max / MAS and how to develop it: VO2max in running: understand and progress.

Used for:

• Short intervals (30s/30s, 1 min/1 min, 400 m repeats)
• VO2max sets: 6 × 2 min at MAS with 2 min recovery

Summary Table of the 5 Zones

Polarized Training: The 80/20 Rule

Research by physiologist Stephen Seiler on elite endurance athletes revealed a simple principle: the best runners perform ~80% of their volume in zones 1-2 and only ~20% in zones 4-5. Very little time is spent in zone 3.

This is the polarized model, also known as 80/20 training. It maximises fundamental aerobic adaptations while incorporating enough quality work to develop the threshold and VO2max, without accumulating chronic fatigue.

In practice for a runner doing 4 sessions/week:

What Equipment to Monitor Your Zones?

Optical Heart Rate Monitors (Wrist-based)

Built into almost all current sports watches (Garmin, Polar, Coros, Apple Watch, Suunto), they measure HR via photoplethysmography (green light). Convenient, but less accurate during short intervals or rapid changes in intensity.

Strengths: no strap, always with you
Weaknesses: measurement lag, less reliable during intervals

Chest Strap Heart Rate Monitors

The chest strap (Polar H10, Garmin HRM-Pro, Wahoo TICKR) remains the gold standard for accuracy. It measures the electrical activity of the heart (ECG), as in a medical setting.

Strengths: near-medical accuracy, ideal for intervals and threshold work
Weaknesses: uncomfortable to wear, requires some moisture to activate

Our recommendation: for daily zone 2 training, wrist-based measurement is sufficient. For quality sessions (intervals, threshold), a chest strap provides more reliable data.

Common Mistakes with Heart Rate Zones

1. Using the 220 - age formula without verification
The discrepancy can reach 15 bpm from reality. Result: all your zones are off, and you train either too hard or not hard enough.

2. Spending too much time in zone 3
The "slightly-too-hard tempo" is the trap for most amateur runners. You feel like you're "training seriously" by pushing a little, but you accumulate fatigue without truly developing either your aerobic base or your threshold.

3. Ignoring hot weather days
In the heat, HR is higher for the same pace. Running in hot weather without adjusting your zones leads to a much more intense actual effort than planned. Trust your HR rather than your pace on those days.

4. Never re-evaluating your zones
Your max HR changes little, but your resting HR can drop by 5-10 bpm after a few months of serious training — which shifts your Karvonen zones. Recalculate every 3 months.

5. Ignoring fatigue to "stay in your zone"
Zones are tools, not absolute rules. If your HR is high despite a slow pace, it's not an opportunity to run faster to "hit your zone" — it's a signal to recover.

Heart Rate Zones and Marathon Goals

Marathon pace typically sits between zone 3 and zone 4 depending on the runner's level. For finishers, it falls in zones 2-3. For elite runners, it sits at the threshold (zone 4). Recovery after a marathon takes place entirely in zone 1, for several weeks.

FAQ — Frequently Asked Questions

My HR spikes quickly at the start of a session — is that normal?
Yes, heart rate has inertia at the start. During the first 5 to 10 minutes of a session, it rises before stabilising. That's why warm-up is essential: it allows the cardiovascular system to adapt progressively.

Why does my HR stay high at the end of a session even when running slowly?
This is "cardiac drift": during long efforts (>1h30), HR tends to rise slightly even at a constant pace, due to dehydration and fatigue. A sign that you need to hydrate better or that the session is reaching its limit.

Is it better to train by heart rate zones or pace?
Both are complementary. Heart rate zones are preferable on hot days, days of fatigue, or when running uphill. Paces are more precise on the track or for targeted quality sessions. Experienced runners use both depending on the context.

My Garmin / Polar zones are different — why?
Each manufacturer uses its own calculation method and zone thresholds. Most default to the 220 - age formula. Configure your watch with your field-tested max HR for greater accuracy.

Zone 2 seems way too easy — does it actually do anything?
That's the question every runner asks the first time they seriously train in zone 2. The answer is yes — provided you're patient. Mitochondrial adaptations take 6 to 12 weeks to fully manifest. Trust the process.

Further Reading

• Fundamental Endurance: the foundations of progress
• VO2max in running: how to calculate and develop it
• Marathon nutrition guide
• Post-marathon recovery guide
• Running in hot weather: adapting your intensity

The values and formulas presented in this article are general references from the sports science literature. They do not replace a medical evaluation or the guidance of a certified coach.