// Cardio Calculators

Heart Rate Zones

Enter your age, and your resting heart rate if you know it, to see your five training zones.

Your details

Your result

Max HR
187bpm
Z1 Recovery (50–60%)
94–112bpm
Z2 Endurance (60–70%)
112–131bpm
Z3 Aerobic (70–80%)
131–150bpm
Z4 Threshold (80–90%)
150–168bpm
Z5 Max (90–100%)
168–187bpm
Zones calculated from
Percentage of max heart rate
  • Without a resting heart rate these are straight percentages of estimated maximum. Add your resting rate above to switch to heart rate reserve, which fits trained people better.
  • No zone burns fat better than another in any way that changes body composition. Total energy and what you eat decide that; zones decide how hard a session feels and how much of it you can repeat.

Estimates are for general guidance only and are not medical advice. For a personalised plan, book a free guided tour at RPM Gym.

What your result means

Five zones, from easy to maximal, and their job is to make the hard days hard and the easy days genuinely easy. Most people who train by feel end up spending everything in zone three — too hard to recover from, too easy to drive adaptation.

If you supplied a resting heart rate, the zones are calculated from heart rate reserve rather than from percentages of your maximum. That's the Karvonen method, and it matters: for someone with a low resting rate every zone floor moves up by ten to fifteen beats, which is the difference between an easy run and a slightly-too-hard one.

Zone two is where most endurance training should sit, and it usually feels slower than people expect. If you can hold a conversation, you're in it. If you're answering in short sentences, you've drifted into zone three.

How to read the categories

Zone 1 — Recovery50-60%Warm-ups, cool-downs and recovery sessions between hard days.
Zone 2 — Endurance60-70%The bulk of aerobic training. Conversational, sustainable for a long time, and the zone most people skip past.
Zone 3 — Aerobic70-80%Moderately hard. Useful in moderation, and the zone that quietly absorbs sessions meant to be easier or harder.
Zone 4 — Threshold80-90%Hard, sustainable for perhaps 20-40 minutes. Where threshold and interval work lives.
Zone 5 — Maximal90-100%Short, very hard intervals. Minutes a week, not hours.

How it is calculated

Percentage of maximum, or heart rate reserve (Karvonen) when a resting rate is supplied

Without resting HR: zone = HRmax × intensity With resting HR: zone = ((HRmax − HRrest) × intensity) + HRrest HRmax is estimated from age using Tanaka: 208 − (0.7 × age)

What it assumes

  • The maximum is an age estimate carrying roughly ten beats of individual variation, and every zone inherits that error.
  • The five-zone model with these percentage bands is a widely used convention rather than a physiological law. Different systems draw the lines in different places and none is definitively correct.
  • Karvonen assumes a genuine resting heart rate — measured on waking, before getting up — not a figure taken while sitting at a desk.
  • Zones describe cardiovascular intensity. They map poorly onto resistance training, where heart rate spikes within a set and drops between sets without a matching energy cost.

Units and rounding

  • Age in whole years; heart rate in beats per minute.
  • Leave resting heart rate at zero to use plain percentages of maximum.
  • A resting rate at or above the estimated maximum is rejected rather than producing inverted zones.

Worked example

A 35-year-old with a measured resting heart rate of 58 bpm.

  1. HRmax = 208 − (0.7 × 35) = 184 bpm
  2. Heart rate reserve = 184 − 58 = 126 bpm
  3. Zone 2 = (126 × 0.6) + 58 to (126 × 0.7) + 58
  4. = 133 to 146 bpm

Zone 2 sits at 133-146 bpm. Using plain percentages of maximum instead, it would read 110-129 — nearly 20 beats lower at the bottom. For a trained person with a low resting rate, that gap is the difference between an easy session and one that barely raises a sweat.

Limitations

  • Everything here inherits the error in the estimated maximum. If your true maximum is ten beats from the prediction, every zone boundary moves with it.
  • Heart rate lags effort. At the start of an interval it's still climbing while you're already working hard, which makes it a poor guide for anything shorter than a few minutes.
  • Heat, dehydration, caffeine, illness and poor sleep all raise heart rate at the same workload. In Abu Dhabi summer, an outdoor session can sit a full zone higher than the same effort indoors.
  • The zones are conventions. A session doesn't stop working because it sat at 71% instead of 69%, and no boundary here is a physiological threshold.
  • They don't apply usefully to lifting. Heart rate in the gym reflects the rest interval more than the training stimulus.

What to do next

  • Measure your resting heart rate properly — on waking, before getting out of bed, averaged over several mornings — and re-run this. It changes the zones more than most people expect.
  • Spend most of your easy sessions in zone two and accept that it feels slow. Discipline on easy days is what makes hard days possible.
  • Use perceived effort as the cross-check. If the monitor says zone two and you can't speak in full sentences, trust your breathing.
  • In summer, expect to sit a zone higher outdoors at the same pace. Train indoors or move the session to after sunset rather than chasing the number.

Sources

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// Frequently Asked

Questions, answered.

What are the five heart rate zones?

Recovery (50-60%), endurance (60-70%), aerobic (70-80%), threshold (80-90%) and maximal (90-100%). The percentages are of your maximum heart rate, or of your heart rate reserve if you've supplied a resting rate.

Is there a fat burning zone?

Not in any way that changes body composition. At lower intensities a higher **share** of the calories burned comes from fat, but the total is smaller — so harder work usually burns more fat in absolute terms as well as more calories. The claim survives because 'higher share' gets read as 'more'.

What is zone 2 training?

Sustained work at 60-70%, easy enough to hold a conversation. It's where most endurance training should sit, and it's the zone people most often skip because it feels too easy to be doing anything.

Should I use resting heart rate to calculate zones?

If you know it, yes. The Karvonen method uses the gap between resting and maximum rather than the maximum alone, and it fits trained people considerably better. For someone with a resting rate in the fifties, plain percentages put the zone floors far too low.

Why is my heart rate higher than usual at the same pace?

Usually heat, dehydration, poor sleep, caffeine or the early stages of illness. Heart rate at a given workload is sensitive to all of them, which is why a single high reading means less than a week of them.

Do heart rate zones work for weight training?

Not well. Heart rate spikes during a set and falls between sets, so a lifting session's average sits in a zone that reflects your rest periods rather than the training you did. Zones are a cardio tool.

Most people train every session at the same medium-hard. Zones exist to stop that.

Zone discipline is hard outdoors in August and straightforward on an air-conditioned cardio floor. Come and see ours on a free guided tour in Al Manhal.

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