Heart rate training zones
Estimate your maximum heart rate with 220 − age, then train by percentage zones. A 30-year-old has an estimated max of 190 bpm. Zone 2 builds aerobic base; zone 4–5 develops top-end speed and VO2max.
| Zone | % of max HR | Feel | Best for |
|---|---|---|---|
| Zone 1 | 50–60% | Very easy, full conversation | Warm-up, recovery, circulation |
| Zone 2 | 60–70% | Easy, can sing | Aerobic base, fat oxidation, long sessions |
| Zone 3 | 70–80% | Moderate, short sentences only | Tempo work, cardiovascular fitness |
| Zone 4 | 80–90% | Hard, few words at a time | Threshold, speed endurance |
| Zone 5 | 90–100% | All-out, cannot talk | VO2max intervals, seconds to minutes |
Notes
- 220 − age is an estimate with ±10–12 bpm individual error; lab testing is precise.
- A resting heart rate of 60–100 bpm is normal; trained endurance athletes often sit at 40–60.
- Zone 2 should feel almost too easy — most recreational athletes train too hard here.
Setting your zones without a lab test
The simplest method is the percentage-of-maximum system used in the table: estimate HRmax with 220 minus your age, then read each zone as a share of it. A 30-year-old at about 190 bpm trains zone 2 between roughly 114 and 133 bpm. The formula carries a plus or minus 10-12 bpm error, though, so treat the numbers as a starting grid. The talk test — full sentences in zone 2, short phrases in zone 3, single words in zone 4 — is free and often more accurate. Runners can refine zones with a 30-minute threshold or heart-rate drift test.
Why most training should stay easy
Polarised training, often summarised as 80/20, puts roughly 80% of sessions in zones 1-2 and 20% in zones 4-5, with little time in the moderate zone 3. Easy work builds capillaries in muscle, improves fat oxidation and lets you accumulate volume without deep fatigue. Zone 2 should feel almost too easy to be useful — conversational and slightly boring. The most common mistake is drifting into zone 3 on easy days, which adds fatigue without the specific adaptations of either slow or hard work.
Intervals: where fitness accelerates
Working at 90-100% of maximum in short repeats is the fastest way to raise VO2max. Classic formats include 4 x 4 minutes in zone 5 with 3 minutes of easy recovery, or 30-second hill sprints. Performance is limited by total time spent near the top, so keep hard sets genuinely hard and stop when you can no longer hold the target. Two interval sessions a week is plenty for most people; more only works when the easy base is large enough to support it.
When your numbers do not match how you feel
Heart rate shifts with conditions that have nothing to do with effort. In heat, blood is diverted to the skin, so the same pace reads 5-10 bpm higher; altitude and dehydration raise it too. Cardiac drift means the rate creeps up during a long steady effort as body temperature rises. Caffeine, stress and illness lift resting and working rates, while beta-blockers flatten them. If a pace that used to sit in zone 2 now spikes into zone 3, look at sleep, hydration and temperature before assuming you have lost fitness.
Resting heart rate as a fitness signal
Resting heart rate is one of the simplest long-term gauges of aerobic fitness. A normal adult range is 60-100 bpm, but trained endurance athletes often sit at 40-60 bpm because a stronger heart moves more blood per beat. Measure it properly: first thing after waking, still lying down, before caffeine or your phone. A gradual downward trend over months usually tracks improving fitness, while a sudden jump of 5-10 bpm above your norm often signals fatigue, dehydration, alcohol or an oncoming illness — a useful early-warning signal for training.
Frequently asked questions
- What is my maximum heart rate?
- A common estimate is 220 minus your age in bpm. A 40-year-old gets about 180 bpm; real values can differ by ±10 bpm.
- Which heart-rate zone burns the most fat?
- Zone 2 uses the highest share of fat as fuel, but total calorie burn and fitness gains are often higher in harder zones — consistency beats zone-picking.
- What is a dangerous heart rate during exercise?
- Stop and seek medical advice if you have chest pain, dizziness or an irregular pounding rhythm; a sustained rate far above your zone without cause warrants attention.