Published 7 June 2026 · 14 min read
TL;DR
- The 5 heart rate zones tell you how hard you are training: Zone 1 is recovery, Zone 5 is all-out. Most beginner training should happen in Zones 1 and 2.
- The classic "220 minus age" max HR formula has a +/-10 bpm error. The Tanaka formula (208 minus 0.7 times age) is more accurate for most adults.
- Edge uses heart rate data from your Strava, Garmin, Apple Watch or Coros sync. Heart rate flows into your training history.
What heart rate zones are
Heart rate zones are a way of dividing your training effort into bands, from very easy to all-out, based on how fast your heart is beating. Each zone targets a different physiological system. Zone 1 builds recovery. Zone 2 builds aerobic base. Zone 3 trains lactate clearance. Zone 4 lifts your threshold. Zone 5 grows your top-end VO2 max. If you only ever train at one effort, you only ever train one system. Zones give you a simple map.
The most common model in UK running is the 5-zone system, adapted from coach Joe Friel and physiologist Andrew Coggan. It uses percentages of your maximum heart rate, the highest your heart can beat in a single minute. So if your max HR is 180 bpm, Zone 2 (60-70% of max) sits between 108 and 126 bpm. The zones are not random. Each one matches a known shift in how your body produces and clears energy.
Why does this matter for a normal runner? Because most beginners train in the wrong zone. They run their easy runs too hard (Zone 3 instead of Zone 2) and their hard runs too soft (Zone 4 instead of Zone 5). The result is a flat, fatigued grey zone that builds neither endurance nor speed. Zones fix that. They give you a number to aim at and a number to back off from.
The 5 zones explained
Zone 1: Recovery (50-60% max HR)
Very easy effort. You can hold a full conversation, sing a song, barely feel like you are working. This is the pace of a cool-down jog, a walk-run shake-out, or a recovery day. Duration: 20-45 minutes. Workout example: 30 minute easy jog the day after a hard session. The point is blood flow, not fitness. You will not get faster doing Zone 1, but you will recover faster and avoid stacking fatigue.
Zone 2: Aerobic base (60-70% max HR)
Conversational pace. You can speak in full sentences with a couple of breaths between them. This is the famous "easy run" zone where your body learns to burn fat for fuel, builds capillaries around your muscles, and grows the mitochondria that power endurance. Duration: 45 minutes to several hours. Workout example: 60 minute steady run where you could hold a chat the whole way. Most weekly mileage should sit here. It feels too easy. That is the point.
Zone 3: Tempo (70-80% max HR)
Comfortably hard. You can speak in short phrases but not full sentences. Lactate is starting to accumulate but your body is still clearing it. This is "marathon pace" effort for many runners. Duration: 20-40 minutes continuous, or longer in blocks. Workout example: 30 minute tempo run at steady "comfortably hard" effort. Use Zone 3 sparingly. It is the famous "grey zone" trap if it eats your easy days.
Zone 4: Threshold (80-90% max HR)
Hard. You can manage one or two words at a time. This is the edge of what you can sustain for 30 to 60 minutes. Lactate is being produced as fast as you can clear it. Threshold sessions are the single biggest lever for half marathon and 10k speed. Duration: 20-40 minutes total work in intervals. Workout example: 4 x 8 minutes at threshold effort with 2 minutes jog between. It should feel hard but controlled.
Zone 5: VO2 max (90-100% max HR)
Max effort. No talking. You are gasping. This zone trains your cardiovascular ceiling, the highest amount of oxygen your body can use per minute. Sessions are short and brutal. Duration: 3-5 minute intervals, 15-25 minutes total work. Workout example: 5 x 3 minutes at all-out effort with 3 minutes jog between. Do once a week at most. Recovery between sessions matters more than the work itself.
How to calculate your max HR
220 minus age (rough)
The classic. Subtract your age from 220. If you are 40, your estimated max HR is 180 bpm. It is simple, it is everywhere, and it is wrong for at least one in three adults. The standard error is plus or minus 10 to 12 bpm. Some 40 year olds have a max HR of 195. Some have 165. The formula will not tell you which. Use it as a starting point, not a finish line.
Tanaka 208 minus 0.7 times age (more accurate)
The Tanaka formula, published in 2001, was built from data on thousands of healthy adults. It reads: max HR = 208 minus (0.7 times age). A 40 year old gets 208 minus 28 = 180 bpm. The result looks similar to 220-age in middle age, but Tanaka is more accurate for women and for adults over 40, who tend to be overestimated by the classic formula. Use Tanaka as your default if you have not done a field test.
Lab test or field test (gold standard)
The most accurate way to know your true max HR is to measure it. A proper lab test on a treadmill with gas analysis is the gold standard, often available at a UK sports science clinic for around £150 to £250. A free field test option: a thorough warm-up, then 3 minutes hard up a hill, jog down, then 3 minutes all-out up the same hill. The peak HR you see in that second effort is close to your true max. Only do this if you are healthy and have a sensible base of fitness. Get a doctor's clearance if you have any cardiac history.
The Karvonen method
The Karvonen method, also called heart rate reserve (HRR), gives more personalised zones by using your resting HR as well as your max HR. The maths: target HR = ((max HR minus resting HR) times percentage) plus resting HR. If your max is 180, your resting is 50, and you want Zone 2 at 65%, that is ((180-50) x 0.65) + 50 = 134.5 bpm. Karvonen tends to push zones a few beats higher than the straight percentage of max method, which better reflects real training intensity for fitter runners with low resting HRs. Our calculator below offers both methods. Try each and see which matches your perceived effort.
5-Zone HR Calculator
Find your 5 heart rate zones
How to actually train by HR zones
Use a chest strap or optical wrist HRM
A chest strap is the most accurate consumer option, particularly for intervals and threshold work where wrist optical sensors often lag or read low during sharp accelerations. Brands like Polar, Garmin, and Wahoo make reliable straps for around £40 to £80. If a chest strap is not for you, a recent Apple Watch, Garmin or Coros wrist HRM is fine for steady-state running. Just know its limits during intervals.
Allow 6-8 weeks of adaptation
Your zones will move as you get fitter. Resting HR drops, max HR stays roughly the same, and the pace you can hold at a given heart rate climbs. Recheck your numbers every 6 to 8 weeks. Do not chase the same pace at the same HR through a plan. Trust the zone, not the pace.
Account for heat, stress, caffeine and sleep
Your heart rate is not just a measure of effort. It is a measure of effort plus everything else your body is dealing with. On a hot day in July, your HR at the same pace can drift up 10 to 15 bpm. After two coffees and a bad night's sleep, the same. Use HR as the truth, slow down when it climbs, and do not punish yourself for a "slow" easy run.
The talk test as cross-check
The talk test is the oldest, simplest cross-check for HR zones. Zone 1 to 2: full sentences. Zone 3: short phrases. Zone 4: one or two words. Zone 5: no talking. If your HR monitor says Zone 2 but you cannot get a sentence out, your HR strap is wrong, or your true max is higher than the formula said. Trust your breath.
The 80/20 rule
The most replicated finding in modern endurance research is the polarised training model, often called 80/20. Elite endurance runners across distances, from 1500m to ultras, spend roughly 80% of their weekly training volume in Zones 1 and 2 (easy) and 20% in Zones 4 and 5 (hard). The middle, Zone 3, gets very little. The lesson for everyday runners is the same. Easy days should be properly easy. Hard days should be properly hard. The flat grey zone of medium effort burns you out and builds neither end of the curve.
Common HR zone mistakes
- Relying on wrist HR for intervals. Optical wrist sensors lag and average. They miss the sharp spike of a 30-second hard rep and read low. For interval and threshold work, a chest strap is worth the £50.
- Ignoring heat-driven HR drift. On a 25C day your HR will sit 8-15 bpm higher at the same pace. Train by HR, not by pace, and accept the slower split.
- Training in Zone 3 too much. The grey zone of "moderately hard" feels productive but flattens your training. Easy days easy. Hard days hard. Avoid the middle.
- Going too hard on easy days. If you cannot hold a conversation, you are not in Zone 2. Slow down, even if it feels embarrassingly easy. Your race fitness comes from these runs.
- Not knowing your actual max HR. Building zones on a formula that is 10 bpm wrong means every zone is wrong. Do a field test or use Tanaka. Do not just take 220-age and run.
How Edge handles HR data
Edge syncs from Strava, Garmin, Apple Watch and Coros, so your heart rate data flows into your training history. Edge does not calculate zones for you or auto-adjust your plan based on heart rate. Use the calculator above to find your zones, then use your wearable to stay in them during runs.
What Edge does give you is an adaptive starting plan built around your goal and your current fitness, Flexi Swap to move sessions when life gets in the way, and lean voice prompts during your runs so you are not staring at a screen. Strength and mobility sessions are built in, with coach video demos. The 17,000+ UK members in the app are running the same plan structure you are. The point of Edge is to make showing up easy. Heart rate zones are how you get faster once you do.
Frequently Asked Questions
What are the 5 heart rate zones for running?
The 5 heart rate zones, expressed as a percentage of your maximum heart rate, are: Zone 1 Recovery (50-60%), Zone 2 Aerobic base (60-70%), Zone 3 Tempo (70-80%), Zone 4 Threshold (80-90%), and Zone 5 VO2 max (90-100%). Most weekly training volume should sit in Zones 1 and 2.
How do I calculate my max heart rate?
The most accurate way is a lab or field test. As a formula, the Tanaka equation (208 minus 0.7 times age) is more accurate than the classic 220 minus age, especially for women and adults over 40. A 35 year old gets a Tanaka estimate of 184 bpm and a 220-age estimate of 185 bpm.
Is the 220 minus age formula accurate?
It is a rough starting point with a standard error of plus or minus 10 to 12 bpm. That means at least one in three adults will have a true max HR that is more than 10 bpm away from the 220-age estimate. Use it for a quick estimate, but use Tanaka or a field test for actual training.
What zone should I run easy in?
Zone 2, 60-70% of max HR. You should be able to hold a full conversation in short bursts between breaths. If you are gasping for air or only managing one or two words, you have drifted into Zone 3 and need to slow down. Easy runs that are too hard are the most common mistake in amateur running.
How much of my training should be in Zone 2?
The polarised training model used by most elite endurance athletes puts around 80% of weekly training volume in Zones 1 to 2 and 20% in Zones 4 to 5. For a beginner running three or four times a week, that means two or three of those runs should be properly easy.
Do I need a chest strap or is wrist HR good enough?
For steady runs in Zones 1 to 3, a recent optical wrist HRM from Garmin, Apple, or Coros is good enough. For intervals and threshold work, where the heart rate spikes and recovers fast, a chest strap is significantly more accurate. If you do a lot of structured speed work, the £50 chest strap is worth it.
