Target Heart Rate & Training Zones Calculator
Determine your personalized 5-zone cardiovascular training spectrum using the clinically validated Karvonen Heart Rate Reserve (HRR) formula and Tanaka equation. Pinpoint your exact beats-per-minute for Zone 2 fat oxidation and aerobic endurance.
The clinical gold standard for target heart rate is the Karvonen Equation: Target HR = HRrest + [(HRmax - HRrest) × % Intensity], where HRmax = 208 - (0.7 × Age) (Tanaka). For Zone 2 Aerobic Conditioning, exercise between 60% and 70% of Heart Rate Reserve (HRR).
Personal Physiology Inputs
Standard formulas like 220 - Age ignore resting heart rate. The Karvonen formula calculates your individual Heart Rate Reserve (127 BPM), preventing under-training in fit individuals and over-training in sedentary adults.
Keep your endurance and recovery runs strictly within Zone 2 by pacing mile and kilometer splits.
Open Running Pace CalculatorYour optimal cardiovascular zone for mitochondrial biogenesis, maximum cellular fat oxidation (up to 85% fat substrate), and all-day aerobic endurance base.
Full 5-Zone Cardiovascular Training SpectrumClick any zone to inspect
Zone 2: Aerobic / Fat Oxidation
Stimulates mitochondrial biogenesis, enhances fat oxidation capacity, builds capillary density in slow-twitch type I muscle fibers.
Wearable Device Zone Mapping
| Device Zone | Target Range | Workout Focus |
|---|---|---|
| Heart Rate Zone 1 | 124 – 136 BPM | Warmup & Circulation |
| Heart Rate Zone 2 | 136 – 149 BPM | Mitochondrial Base & Endurance |
| Heart Rate Zone 3 | 149 – 162 BPM | Cardiovascular Stamina & Marathon Pace |
| Heart Rate Zone 4 | 162 – 174 BPM | Anaerobic Capacity & Lactate Clearance |
| Heart Rate Zone 5 | 174 – 187 BPM | Peak Sprint Power & Maximum Oxygen Uptake |
Cardiovascular Clinical Notice: Heart rate formulas provide population-level estimates. If you are taking beta-blockers, blood pressure medications, or have a history of cardiovascular disease, age-based equations are inaccurate. Consult a physician or undergo a clinical Bruce Protocol treadmill stress test.
The Physiology of Zone 2 & Energy Substrates
Why Zone 2 is the Foundation of Longevity & Performance
In endurance physiology, Zone 2 represents the highest intensity at which your body can sustain energy production predominantly via free fatty acid oxidation without substantial accumulation of blood lactate (keeping blood lactate typically below 2.0 mmol/L).
Consistent Zone 2 training stimulates mitochondrial proliferation (biogenesis), enhances capillary density in slow-twitch muscle fibers, and increases fatty acid translocase enzymes, allowing you to run, cycle, and swim faster while sparing precious intra-muscular glycogen.
The 80/20 Polarized Training Rule
Elite endurance athletes (marathon runners, Tour de France cyclists, Olympic cross-country skiers) spend approximately 80% of their weekly training volume in Zone 1 and Zone 2, reserving only 15%–20% for high-intensity threshold and VO2 max intervals (Zone 4 and Zone 5).
A common amateur training error is the "Zone 3 Trap"—training too fast on easy days to stimulate recovery, and too tired on hard days to achieve maximal neuromuscular output.
References & Clinical Citations:
1. Karvonen, M. J., Kentala, E., & Mustala, O. (1957). The effects of training on heart rate; a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3), 307–315.
2. Tanaka, H., Monahan, K. D., & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1), 153–156.
3. Gellish, R. L., et al. (2007). Longitudinal modeling of the relationship between age and maximal heart rate. Medicine & Science in Sports & Exercise, 39(5), 822–829.
4. San-Millán, I., & Brooks, G. A. (2018). Assessment of Metabolic Flexibility by Means of Measuring Blood Lactate in Elite Athletes and Metabolic Disease Patients. Sports Medicine, 48(2), 467–479.