Heart Rate Zone Calculator

What Are Heart Rate Zones?

Heart rate zones are ranges of heart beats per minute that correspond to different training intensities and physiological benefits. Training in specific zones helps target different energy systems and adaptations, making your training more efficient and purposeful.

The Five Training Zones

• Zone 1 - Recovery (50-60% max HR): Very easy effort for warm-up, cool-down, and recovery. Promotes blood flow and aids recovery without adding training stress.
• Zone 2 - Aerobic Endurance (60-70% max HR): Easy conversational pace. Builds aerobic base, improves fat burning, and develops mitochondrial density. This is where most of your training should happen.
• Zone 3 - Tempo (70-80% max HR): Moderate intensity, steady state running. Improves aerobic efficiency and is comfortable but not easy. Good for marathon pace work.
• Zone 4 - Lactate Threshold (80-90% max HR): Hard but sustainable effort. Threshold runs and tempo workouts. Trains your body to clear lactate more efficiently and improves your ability to sustain hard efforts.
• Zone 5 - VO2 Max (90-100% max HR): Very hard intensity. Interval training, hill repeats, and race pace for 5K and shorter. Improves maximum aerobic capacity and running economy.

Maximum Heart Rate vs Lactate Threshold

There are two main methods for calculating heart rate zones:

• Maximum Heart Rate Method: Uses percentages of your max heart rate. Easier to determine but less personalized. Max HR can be found through a max effort test or estimated using 220 minus your age.
• Lactate Threshold Method: Uses percentages of your LTHR. More accurate for individual physiology but requires testing. LTHR is typically found through a 30-minute time trial at maximum sustainable effort (average HR from the last 20 minutes).

How to Find Your Maximum Heart Rate

Options for determining max HR:

• Lab Test: Most accurate, conducted on a treadmill or track with heart rate monitoring
• Field Test: After thorough warm-up, run a 5-10 minute all-out effort. Your highest recorded HR is close to your max
• Age Formula: 220 - age is a rough estimate but can be off by 10-20 bpm for individuals

Warning: Max HR tests are extremely demanding. Only attempt if you're fit and healthy. Consult a doctor if you have any health concerns.

How to Find Your Lactate Threshold Heart Rate

The simplest field test for LTHR:

1. Warm up thoroughly for 10-15 minutes
2. Run a 30-minute time trial at the hardest pace you can sustain for the full duration
3. Your LTHR is the average heart rate from the last 20 minutes

This should be done on a flat course without wind, when fresh and well-rested. The effort should feel hard but controlled - about 10K race effort.

Training Distribution

Research and elite coaching support the 80/20 rule:

• 80% easy: Most training should be in Zones 1-2 at conversational pace. This builds aerobic base without excess fatigue.
• 20% hard: Zones 3-5 for tempo runs, threshold work, and intervals. This provides the stimulus for improvement.

Many runners make the mistake of running their easy days too hard and their hard days not hard enough, leading to chronic fatigue and limited improvement.

Using Heart Rate for Training

• Use HR zones as a guide, not an absolute rule - pace, terrain, and conditions all matter
• Heart rate lags behind effort - it takes time to rise and fall
• External factors affect HR: heat, humidity, fatigue, stress, caffeine, dehydration
• Cardiac drift causes HR to rise during long runs even at steady pace
• HR is most useful for keeping easy days easy and monitoring recovery

Sample Training Week

How zones might look in a typical training week:

• Monday: Rest or Zone 1 recovery run (20-30 min)
• Tuesday: Zone 4 threshold workout (warm-up + 3 x 10 min at threshold + cool-down)
• Wednesday: Zone 2 easy run (45-60 min)
• Thursday: Zone 5 intervals (warm-up + 6 x 800m with recovery + cool-down)
• Friday: Zone 1 recovery run (30 min)
• Saturday: Zone 2 long run (90-120 min)
• Sunday: Rest or Zone 2 easy run (30-45 min)

Important Notes

• These zones are guidelines - individual variation is normal
• Retest your max HR or LTHR every few months as fitness changes
• Don't obsess over hitting exact numbers - perceived effort matters too
• If you're new to heart rate training, it will take time to learn what each zone feels like
• Consider using both HR and pace data together for best results