Calculates 5 heart-rate zones (Recovery, Fat Burn, Cardio, Anaerobic, Peak) using max-HR formulas (Fox, Tanaka, Gulati) and Karvonen with optional resting HR. AHA standard.
| Formula | Year | Equation | HRmax |
|---|---|---|---|
| Fox: 220 − age (most common) | 1971 | 220 − age | 190 bpm |
| Tanaka: 208 − 0.7 × age (older adults) | 2001 | 208 − 0.7 × age | 187 bpm |
| Gulati: 206 − 0.88 × age (women) | 2010 | 206 − 0.88 × age | 180 bpm |
Target HR = resting HR + (max HR − resting HR) × intensity%. Reflects resting HR for personalized intensity.
| Zone 1 (50–60%) | Circulation recovery / injury prevention / beginner-friendly |
| Zone 2 (60–70%) | Aerobic base / fat oxidation peak / long-duration |
| Zone 3 (70–80%) | VO2max improvement / cardiac strengthening |
| Zone 4 (80–90%) | Lactate threshold / race-pace adaptation |
| Zone 5 (90–100%) | Peak power / speed / HIIT short intervals |
This Korea-friendly reference calculator uses standard formulas from the American Heart Association, Tanaka (2001), Gulati (2010), and Karvonen. HRmax is a statistical estimate with ±10–12 bpm error; an exact value requires a Korean exercise stress test (GXT). This tool is not medical or training advice. Korean adults with cardiovascular disease, hypertension, diabetes, on heart medication, or pregnant must consult a Korean physician or qualified trainer before exercising. Stop immediately on chest pain, dizziness or breath difficulty. This tool does not promote any equipment, drug or supplement and is unaffiliated with AHA or the Korean Society of Cardiology.
Heart-rate zones split intensity by % of max HR (HRmax). The most popular Fox formula (HRmax = 220 − age, 1971) carries ±10–12 bpm error; Tanaka (208 − 0.7 × age) suits older adults and Gulati (206 − 0.88 × age) suits women. The AHA 5-zone split — Zone 1 (50–60%, recovery), Zone 2 (60–70%, fat burn), Zone 3 (70–80%, aerobic), Zone 4 (80–90%, anaerobic), Zone 5 (90–100%, peak) — is standard. The Karvonen formula uses resting HR for personalized targets. WHO and AHA recommend 150 min/week moderate or 75 min/week vigorous aerobic activity.
Fox (220 − age) is most popular but has ±10–12 bpm error. Tanaka is more accurate for adults 40+; Gulati for women. Korean exercise stress test (GXT) is the gold standard.
Right after wake-up, count pulses for 1 minute at the wrist or carotid. Normal Korean adult: 60–80 bpm; trained athlete: 40–60 bpm. Use the weekly average.
Zone 2 burns a higher % from fat, but higher zones burn more total calories. Combining both is most efficient — caloric deficit ultimately drives weight loss.
Wrist optical (PPG) sensors lag chest straps by ±5–10 bpm, more during interval/high-intensity. Polar/Garmin Korean chest straps are more accurate.
No — beta-blockers can lower HRmax by 30–50 bpm. Korean cardiac patients must follow a physician's HR prescription, not a generic formula.
Not recommended. Zone 5 needs 48–72 hours recovery; 1–2 weekly intervals is typical. Daily Zone 5 risks Korean overtraining and injury.
Heart-rate zones split exercise intensity by percent of max heart rate (HRmax); the AHA's 5-zone split is the standard. This calculator applies three Korean-friendly HRmax formulas — Fox (1971: 220 − age), Tanaka (2001: 208 − 0.7 × age, accurate for older adults), and Gulati (2010: 206 − 0.88 × age, women) — plus the Karvonen formula (target HR = resting + (max − resting) × intensity%) for personalized zones. Zone 1 (50–60%): recovery / warm-up / cool-down; Zone 2 (60–70%): fat burn / endurance, 30–60 min; Zone 3 (70–80%): aerobic / VO2max, 20–40 min; Zone 4 (80–90%): lactate threshold / race pace, 10–20 min; Zone 5 (90–100%): peak / VO2max / HIIT, ≤5 min. WHO and AHA recommend 150 min/week moderate (Zone 2–3) or 75 min/week vigorous (Zone 4–5). HRmax formulas have ±10–12 bpm error; only a Korean exercise stress test (GXT) gives an exact value. Beta-blocker users may have HRmax 30–50 bpm lower and must follow a Korean physician's prescription. Wrist optical sensors are ±5–10 bpm vs chest straps. Korean adults with cardiovascular disease, hypertension, diabetes, pregnancy, or on heart medication must consult a Korean physician before exercising; stop immediately on chest pain, dizziness, or breath difficulty.