Training Zone Calculator
Calculate your personalized heart rate and pace training zones for optimal workout intensity and performance gains.
Heart Rate Zones
We'll estimate max HR using 220 - age
Pace Zones (Optional)
Enter your recent 5K time to calculate pace zones
What Are Training Zones?
Training zones are specific ranges of exercise intensity that target different physiological adaptations. By training in different zones, you can improve various aspects of your running fitness: endurance, speed, lactate threshold, and VO2 max.
Heart rate zones are based on percentages of your maximum heart rate, while pace zones are calculated from your current race performance. Using both together gives you the most accurate training intensity guidance.
Understanding Each Zone
Zone 1: Recovery (50-60% max HR)
Used for active recovery runs, warm-ups, and cool-downs. You should be able to hold a full conversation easily. Most runners spend too little time here.
Zone 2: Aerobic (60-70% max HR)
The foundation of endurance training. This is where you build your aerobic base and improve fat metabolism. Should make up 70-80% of your total training volume.
Zone 3: Tempo (70-80% max HR)
Improves lactate threshold and running economy. This is your "comfortably hard" pace - you can speak in short sentences but not hold a conversation.
Zone 4: Threshold (80-90% max HR)
Pushes your lactate threshold higher and improves speed endurance. This is a hard effort where talking is minimal to none. Used for tempo intervals and threshold workouts.
Zone 5: VO2 Max (90-100% max HR)
Maximum intensity intervals that improve your VO2 max and top-end speed. These are very hard efforts with no talking, typically done as short intervals (3-5 minutes) with rest periods.
Simple vs. Karvonen Formula
Simple Formula (220 - age)
Quick and easy, but less accurate. Uses only your age to estimate maximum heart rate. Good starting point for beginners.
Karvonen Formula (with resting HR)
More accurate as it accounts for your resting heart rate and heart rate reserve. Better for experienced runners who know their resting HR.
How to Use Training Zones
- 80/20 Rule: Spend 80% of training time in Zones 1-2 (easy) and 20% in Zones 3-5 (hard)
- Zone 2 Focus: Build your aerobic base with long, easy runs in Zone 2
- Quality Workouts: Use Zones 4-5 for interval sessions once or twice per week
- Tempo Runs: Zone 3 for sustained threshold efforts (20-40 minutes)
- Recovery Days: Stay in Zone 1 the day after hard workouts
- Race Effort: 5K in Zone 5, 10K in Zone 4, Half/Marathon in Zone 3
Scientific Basis
Training zone methodology is built on decades of exercise science research demonstrating how different intensity levels produce specific physiological adaptations.
Karvonen Heart Rate Formula
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.
The Karvonen formula (Target HR = ((HRmax - HRrest) × %Intensity) + HRrest) provides more accurate training zones than simple percentage methods by accounting for individual resting heart rate. This Heart Rate Reserve method better reflects actual cardiovascular stress and training intensity.
80/20 Training Principle
Seiler, S., & Tønnessen, E. (2009). "Intervals, thresholds, and long slow distance: the role of intensity and duration in endurance training." Sportscience, 13, 32-53.
Dr. Stephen Seiler's research on elite endurance athletes revealed they consistently train approximately 80% of time at low intensity (Zones 1-2) and 20% at high intensity (Zones 4-5). This polarized training distribution optimizes adaptation while minimizing injury risk and overtraining.
Heart Rate Zone Origins
Robergs, R. A., & Landwehr, R. (2002). "The surprising history of the 'HRmax=220-age' equation." Journal of Exercise Physiology Online, 5(2), 1-10.
This analysis examined the widely-used 220-age formula and its limitations (±10-12 bpm standard deviation). While simple and accessible, the formula should be validated with actual max HR testing when possible, especially for competitive athletes requiring precise training zones.
Training Intensity Distribution
Esteve-Lanao, J., et al. (2005). "Impact of training intensity distribution on performance in endurance athletes." Journal of Strength and Conditioning Research, 19(4), 943-949.
This controlled study demonstrated that runners following a polarized intensity distribution (large volume in Zone 2, small volume in Zones 4-5) showed greater performance improvements than those training predominantly at moderate intensity (Zone 3). The research validates the importance of spending most training time in specific zones.
Scientific Validation
Zone-based training is one of the most researched aspects of endurance training. Studies consistently show that training at specific intensities produces predictable adaptations: Zone 2 builds aerobic base and mitochondrial density, Zone 3 improves lactate threshold, and Zone 5 enhances VO2 max. The five-zone model used here is supported by both physiological markers and performance outcomes across skill levels.
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