Heart Rate Zones Calculator

Training in the correct heart rate zone ensures you are stimulating the right energy systems and avoiding unnecessary fatigue. While most sports watches lock you into a single generic calculation, Apex Run allows you to set custom heart rate zones manually.

Use the interactive calculator above to determine your zones with the method that best matches your training philosophy, then enter them in Settings → Heart Rate Zones in the Apex Run App.

The Three Calculation Methods

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This calculator supports three of the most popular and scientifically validated methods for defining running zones.

1. Maximum Heart Rate Method (Max HR %)

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The simplest and most common method. It defines zones as direct percentages of your maximum heart rate.

• Best for: Beginners who do not know their resting heart rate or threshold heart rate.
• Formula: Zone boundary = Max HR × percentage
• Adaptation: Very straightforward, but it doesn’t account for individual differences in fitness level or resting heart rate.

2. Karvonen Method (Heart Rate Reserve - HRR)

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A more advanced method that factors in your Resting Heart Rate. The range between your resting and maximum heart rate is called your Heart Rate Reserve (HRR).

• Best for: Intermediate to advanced runners. It scales zones based on your cardiovascular fitness (as you get fitter, your resting HR drops, which dynamically adjusts your training zones).
• Formula: Zone boundary = (HRR × percentage) + Resting HR, where HRR = Max HR − Resting HR.
• Adaptation: More closely tracks your actual physiological strain compared to the simple Max HR method.

3. Lactate Threshold Heart Rate Method (LTHR)

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The gold standard for serious endurance training, popularized by coach Joe Friel. Your Lactate Threshold is the maximum effort you can sustain for about an hour without lactate rapidly accumulating in your blood.

• Best for: Serious runners, marathoners, and triathletes who want to optimize their training intensity.
• Formula: Zones are mapped as percentages relative to your LTHR.
  • Zone 1 (Recovery): < 85% of LTHR
  • Zone 2 (Aerobic Base): 85% to 89% of LTHR
  • Zone 3 (Tempo): 90% to 94% of LTHR
  • Zone 4 (Threshold): 95% to 99% of LTHR
  • Zone 5 (Maximum): >= 100% of LTHR
• Adaptation: Highly specific to running performance. Zone 2 in the LTHR method is typically higher and more accurate than in the Max HR method, allowing you to train faster while remaining purely aerobic.

How to Find Your True Heart Rate Numbers

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Generic age-based formulas (like 220 - Age) are estimates and can be off by up to 10-15 bpm. To get accurate training zones, it is highly recommended to perform field tests to measure your real numbers.

Finding Your Max HR (Field Test)

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• Warm-up: Run easy for 10-15 minutes, including a few short accelerations.
• Test: Find a steep hill that takes about 1-2 minutes to run up. Run up the hill at a hard effort (about 5K pace), then jog back down. Run up again, pushing harder. On the third run, sprint up the hill as hard as you possibly can.
• Result: The highest heart rate recorded on your heart rate monitor during the final hill sprint is a very close estimate of your actual Max HR.

Finding Your LTHR (30-Minute Time Trial)

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• Warm-up: Run easy for 10 minutes.
• Test: Perform a 30-minute solo time trial (run as fast as you can sustain at a steady pace for the entire 30 minutes). Crucial: Start your heart rate monitor lap button exactly 10 minutes into the run.
• Result: Your average heart rate over the final 20 minutes of the test is a highly accurate estimate of your Lactate Threshold Heart Rate (LTHR).

Applying Zones in Apex Run

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Once you have calculated your custom zones above:

1. Open the Apex Run App.
2. Navigate to Settings → Zone Settings.
3. Manually adjust the boundaries for Zone 1 through Zone 5 to match your calculated numbers (or tap “Reset to Default Settings” to start over).
4. Tap Save. These updates will instantly reflect across your entire running history, run analysis charts, and weekly training structure metrics.