Heart Rate Zones: How to Calculate and Train in Each Zone

Heart rate zones divide exercise intensity into bands based on your maximum heart rate, so you can tell an easy session from a hard one by numbers rather than feel. Below: how to calculate them (with and without resting heart rate), what each zone is used for, and how to combine them in a week.

Understanding the Five Heart Rate Training Zones

The common five-zone model uses percentages of your maximum heart rate (MHR). Exact boundaries differ between coaches and device makers, so treat these as typical values.

Zone 1 (50-60% MHR): Active recovery and very light activity. You can hold a full conversation. Example: For someone with a 180 bpm max heart rate, this zone spans 90-108 bpm.

Zone 2 (60-70% MHR): Easy endurance training. You can still talk comfortably. Fat supplies a large share of the energy, and this is where endurance athletes do much of their volume.

Zone 3 (70-80% MHR): Moderate intensity, fuelled by a mix of fat and carbohydrate. Conversation shrinks to short phrases.

Zone 4 (80-90% MHR): Hard training around lactate threshold, fuelled mostly by carbohydrate. Talking is very difficult.

Zone 5 (90-100% MHR): Maximum effort training that develops neuromuscular power and speed. Sustainable only for short periods, with speaking nearly impossible.

How Heart Rate Zone Calculator Works

The calculation starts with maximum heart rate. The simplest estimate is 220 minus your age; the Tanaka formula (208 − 0.7 × age), published in 2001, fits measured values better in older adults. Both are population averages, and an individual's true maximum can differ by 10 beats a minute or more.

For a 35-year-old, 220 − 35 = 185 bpm. Zone 2 then spans 111–130 bpm (60–70% of 185), and Zone 4 148–167 bpm (80–90% of 185).

The Karvonen method also uses your resting heart rate. This method calculates heart rate reserve (maximum heart rate minus resting heart rate) and applies the percentage to this range before adding back the resting heart rate. For someone with a 185 bpm maximum and a 65 bpm resting rate, heart rate reserve is 120 bpm, so Zone 2 becomes 65 + (0.6 to 0.7 × 120) = 137–149 bpm rather than 111–130 bpm.

The heart rate zone calculator takes your age, resting heart rate and method (Karvonen, percentage of 220 − age, or Tanaka) and returns the 70% figure (labelled "Zone 3 target"), which is the boundary between Zones 2 and 3; multiply by other percentages for the remaining boundaries.

Training Benefits of Each Heart Rate Zone

Zone 1 is for recovery: easy movement between harder sessions that adds little stress.

Zone 2 builds the aerobic base that endurance depends on, and you can do a lot of it without needing long recovery.

Zone 3 improves aerobic fitness too, but many coaches call it a "gray zone": harder than easy days need to be, yet not hard enough for the biggest high-end gains.

Zone 4 work raises your lactate threshold (the intensity above which lactate builds up faster than you clear it), so you can hold faster paces for longer. Harder work also burns more calories per minute; the calories burned calculator estimates the total for an activity from body weight, duration and the activity's MET value, and for a run the Running Calorie Calculator estimates the total from weight, distance, pace and terrain.

Zone 5 develops maximum speed and power. It is very demanding and needs plenty of recovery.

How to Use Our Calculator for Optimal Results

Measure resting heart rate first thing in the morning before getting up: count for 60 seconds on three mornings and average. For adults, 60–100 bpm is the normal range, and well-trained endurance athletes can be as low as about 40.

Check the zones against how workouts feel. Zone 1 should feel almost effortless, Zone 2 easy enough to breathe through your nose, and Zone 4 comfortably hard, sustainable for roughly 20–40 minutes. Most watches and chest straps can be set to your own zone boundaries and alert you when you drift.

Heat, humidity, stress, caffeine, dehydration and fatigue all push heart rate up at a given effort, so treat the zones as guidelines. The formulas are population estimates, not a medical test; anyone with a heart condition, or taking medication that affects heart rate such as a beta blocker, should get training ranges from a clinician.

Practical Training Applications and Programming

The "80/20" pattern comes from Stephen Seiler's studies of elite endurance athletes, who spend roughly 80% of their training at low intensity and about 20% at moderate to high intensity. Many coaches apply a similar split for recreational athletes.

For beginners, start with three weekly sessions: two Zone 2 workouts lasting 30-45 minutes and one Zone 3-4 session of 20-30 minutes. As fitness improves, gradually increase duration before adding intensity. A sample week might include a 45-minute Zone 2 bike ride, a 40-minute Zone 2 walk or easy run, and a 25-minute session alternating between Zone 3 and Zone 4 intervals.

Intermediate athletes can handle four to five sessions weekly, incorporating specific zone targets based on goals. Endurance-focused athletes might include longer Zone 2 sessions (60-90 minutes), weekly Zone 4 threshold work (2-3 intervals of 8-12 minutes), and monthly Zone 5 sessions for neuromuscular development.

Advanced athletes often periodize their training, emphasizing different zones throughout the season. Base-building phases prioritize Zone 1-2 training, building aerobic capacity and fat-burning efficiency. Competition phases incorporate more Zone 4-5 work to sharpen performance and raise lactate threshold.

Watch your resting heart rate, sleep and energy. A resting heart rate that stays elevated, or performance that drops despite the same effort, can signal that you need more easy days and recovery.

Related guides

• BMR vs TDEE Explained: Which Number Should You Use?
• Calorie Deficit: How to Calculate and Use It for Weight Loss

Sources

• Tanaka, Monahan & Seals, Journal of the American College of Cardiology 2001 — Age-predicted maximal heart rate revisited (PubMed)
• CDC — How to Measure Physical Activity Intensity
• Stöggl & Sperlich, Frontiers in Physiology 2015 — The training intensity distribution among well-trained and elite endurance athletes (reviews Seiler's 80/20 findings)