Your five training zones in actual beats per minute — from your age or measured max — plus what each zone does and how hard it should feel.
Your numbers
years
bpm
Max heart rate used
187bpm
Tanaka estimate (208 − 0.7 × age) — replace with a measured max if you have one
130 bpm — Zone 2, Endurance
Slide to any heart rate to see which zone it lands in. Zone boundaries are % of max HR.
Your five zones
Zone
% max HR
Heart rate
Z1 · Recovery
50–60%
94–112 bpm
Z2 · Endurance
60–70%
112–131 bpm
Z3 · Tempo
70–80%
131–150 bpm
Z4 · Threshold
80–90%
150–168 bpm
Z5 · Maximal
90–100%
168–187 bpm
Zone 1 · 94–112 bpm
Recovery
Promotes blood flow and recovery without adding fatigue. Warm-ups, cool-downs, easy days.
Zone 2 · 112–131 bpm
Endurance
Builds the aerobic base — mitochondria, capillaries, fat metabolism. Where most training volume belongs.
Zone 3 · 131–150 bpm
Tempo
Comfortably hard, steady-state work. Improves sustained pace but accumulates real fatigue.
Zone 4 · 150–168 bpm
Threshold
Around the lactate threshold. Raises the pace you can hold for 30–60 minutes. Use in measured doses.
Zone 5 · 168–187 bpm
Maximal
VO₂max intervals and finishing kicks. Minutes per week, not hours — potent and costly.
Zones from an age-estimated max carry that estimate’s ±10 bpm individual error — every boundary shifts with it. Add your resting HR for Karvonen (HRR) zones, which are better anchored to your actual fitness.
The five-zone model
Heart rate zones exist because “go for a run” is not a training prescription. Different intensities produce different adaptations — easy volume grows the aerobic machinery, threshold work raises sustainable pace, sprints build top-end power — and heart rate is the cheapest window into which one you are actually doing. The common five-zone scheme slices the top half of your heart rate range into 10-percentage-point bands:
zone floor = HRmax × lower% e.g. Z2 = HRmax × 0.60 … 0.70
Karvonen variant (uses resting HR):
zone floor = (HRmax − HRrest) × lower% + HRrest
The calculator uses %HRmax boundaries — Z1 50–60%, Z2 60–70%, Z3 70–80%, Z4 80–90%, Z5 90–100% — and, if you enter a resting heart rate, also shows the Karvonen (heart rate reserve) version, which anchors zones to your fitness rather than your age alone. Our target heart rate calculator digs into why that distinction matters.
What each zone feels like and trains
Zone
% max
Talk test
What it develops
Z1 · Recovery
50–60%
Could chat for hours
Circulation, recovery between hard days
Z2 · Endurance
60–70%
Full sentences, nose breathing possible
Mitochondria, fat metabolism, aerobic base
Z3 · Tempo
70–80%
Short sentences
Sustained “comfortably hard” pace
Z4 · Threshold
80–90%
A few words
Lactate threshold — race pace for 30–60 min
Z5 · Maximal
90–100%
No talking
VO₂max, sprint power — minutes per week
Why Zone 2 dominates serious training
Analyses of how elite endurance athletes actually train — rowers, cyclists, distance runners, cross-country skiers — keep finding the same lopsided pattern: roughly 80% of sessions easy, 20% hard, with surprisingly little time in the middle. The logic is economic. Zone 2 delivers most of the aerobic signal (more mitochondria, denser capillaries, better fat oxidation) at a fraction of the recovery cost, so you can accumulate a lot of it. Hard work delivers adaptations easy work cannot, but the dose you can absorb is limited. Spending easy days too hard — the classic Zone 3 drift — buys little extra adaptation while eroding the quality of the hard days.
Two honest caveats. The 80/20 evidence comes largely from athletes training many hours a week; if you train three hours a week, the case for polarising is weaker and some quality tempo work goes a long way. And the “80” counts easy sessions, not a magic ratio to obsess over — the practical rule is simply: easy days genuinely easy, hard days genuinely hard.
Zones lie a little — calibrate by feel too
Heart rate is a proxy with known failure modes. It lags effort by a minute or two, so short intervals out-run it. It drifts upward on long, hot sessions at constant pace (cardiovascular drift), quietly promoting you a zone. Caffeine, stress, illness and dehydration all shift it. And wrist optical sensors can misread badly during high-intensity or gripping work — a chest strap is more trustworthy when zone precision matters. The fix is to cross-reference the number with the talk test in the table above: if the watch says Zone 2 but you cannot speak a paragraph, believe your breathing.
The bigger systematic error is the max HR your zones are built on. Device defaults usually assume 220 − age, which misses real maxima by 10 or more bpm in both directions — enough to shift every boundary a full zone for some people. If your easy runs always read “Zone 3” despite feeling effortless, your configured max is probably wrong. The max heart rate calculator compares the four main formulas and describes a proper field test; for a sense of the engine these zones are training, see the VO₂max calculator.
Frequently asked questions
What are the 5 heart rate zones?+
In the common five-zone model: Zone 1 is 50–60% of max HR (recovery), Zone 2 is 60–70% (aerobic endurance), Zone 3 is 70–80% (tempo), Zone 4 is 80–90% (threshold), and Zone 5 is 90–100% (maximal efforts). For a max HR of 187, Zone 2 runs roughly 112–131 bpm.
What heart rate zone should I train in most?+
Zone 2. Well-studied endurance athletes typically do around 80% of their training at easy, conversational intensity and only about 20% hard — the so-called 80/20 split. Easy volume builds the aerobic engine while staying recoverable; hard sessions then sharpen it.
What heart rate zone burns the most fat?+
Zone 2 burns the highest proportion of calories from fat, which is where the 'fat-burning zone' idea comes from. But total fat loss depends on your overall calorie balance, not the fuel mix during exercise — harder sessions burn more total calories per minute. Train Zone 2 for endurance, not as a fat-loss trick.
Why does my heart rate drift up at the same pace?+
Cardiovascular drift — during long or hot sessions your heart rate creeps upward even at constant effort, as you dehydrate and shunt blood to the skin for cooling. It can push you a zone higher without any pace change, which is a reason to also calibrate effort by breathing and the talk test.
How accurate are watch heart rate zones?+
Two separate errors stack: wrist optical sensors can misread during intervals or weight training (chest straps are more reliable), and most watches default to zones from 220 − age, which can be 10+ bpm off your real max. Fix the max HR setting first — it moves every zone boundary.
Should I use max HR zones or Karvonen (HRR) zones?+
Percent-of-max zones are the common default and work fine if your max HR is accurate. Karvonen zones additionally use your resting heart rate, so they scale with your fitness and map better onto metabolic effort — worth using if you know your resting HR. This calculator shows both side by side.