Enter your age to instantly calculate all 5 heart rate training zones based on your estimated maximum heart rate. Find your fat-burning, aerobic, and threshold zones.
Heart rate zones are the foundation of structured endurance training. By understanding which zone you are exercising in, you can target specific physiological adaptations — whether that is burning fat efficiently, building your aerobic base, improving lactate threshold, or developing peak speed. Training without zones is like driving without knowing your speed: you might get somewhere, but not necessarily where you want to go.
Heart rate zones are expressed as percentages of your maximum heart rate (Max HR). This makes them personalised: two people of the same age but different fitness levels will have different absolute bpm values for each zone, because individual maximum heart rates vary significantly.
Very light exercise. Warm-up, cool-down, active recovery between hard sessions. You can hold a full conversation effortlessly. Fat is the primary fuel source.
Easy aerobic exercise. Sustainable for hours. Develops mitochondrial density, fat oxidation, and cardiovascular efficiency. The cornerstone of endurance training.
Moderate intensity aerobic training. Improves cardiovascular fitness and economy. Can be sustained for 30–60 minutes. Breath is noticeably elevated but manageable.
Lactate threshold training. Hard effort, can only speak in short phrases. Improves your anaerobic threshold — the pace you can sustain in races. Classic tempo run zone.
Near-maximum or maximum effort. Sprint intervals, 400m running, final race surges. Cannot be sustained for more than 1–2 minutes. Develops peak power and VO2 max.
Using the Tanaka formula (208 − 0.7 × 35 = 183.5 bpm ≈ 184 bpm max HR):
| Zone | % of Max HR | BPM Range (Age 35) | Activity Examples |
|---|---|---|---|
| Zone 1 | 50–60% | 92–110 bpm | Walking, easy cycling, warm-up |
| Zone 2 | 60–70% | 110–129 bpm | Easy jog, cycling, swimming laps |
| Zone 3 | 70–80% | 129–147 bpm | Brisk run, moderate cycling |
| Zone 4 | 80–90% | 147–166 bpm | Tempo run, hard cycling intervals |
| Zone 5 | 90–100% | 166–184 bpm | Sprint intervals, all-out effort |
Research into elite endurance athletes reveals a consistent pattern: approximately 80% of their training volume is performed at low intensity (Zone 1 and Zone 2), while the remaining 20% is at high intensity (Zone 4 and Zone 5). This is known as the 80/20 or polarised training model, popularised by exercise scientist Dr Stephen Seiler.
Recreational athletes often make the mistake of training too hard too often — doing most of their training in Zone 3, which is too easy to provide the high-intensity stimulus and too hard to allow rapid recovery. This results in a "grey zone" training pattern that produces mediocre adaptations and accumulated fatigue.
Zone 2 training is experiencing a renaissance in endurance sports. At 60-70% of maximum heart rate, you are exercising aerobically — your body primarily burns fat for fuel and can sustain the effort for extended periods (1-3 hours or more for well-trained athletes). This zone stimulates mitochondrial biogenesis — the creation of more mitochondria in muscle cells — which is the primary determinant of long-term aerobic capacity.
For beginners, Zone 2 may feel surprisingly easy. If you are breathing heavily during what should be Zone 2 running, slow down or walk. The conversational pace — where you can speak in full sentences without gasping — is a reliable indicator you are in Zone 2.
Your resting heart rate (measured first thing in the morning, before getting out of bed) is an excellent indicator of cardiovascular fitness. The average resting heart rate is 60–100 bpm. Endurance-trained athletes often have resting heart rates of 40–60 bpm. Regular aerobic exercise causes the heart to become stronger and pump more blood per beat, reducing the number of beats needed at rest.
Tracking your resting heart rate over weeks and months provides a concrete measure of fitness improvement. A decreasing resting heart rate is a strong signal of improving cardiovascular health.
For more precise zone calculations, the Karvonen method accounts for your resting heart rate (HR Reserve = Max HR − Resting HR). Target HR = Resting HR + (HR Reserve × Zone%).
Our calculator above uses resting HR (when provided) to calculate Karvonen-adjusted zones, which are more accurate for individuals with very high or low resting heart rates.