Among all cycling metrics, "heart rate" is one of the indicators that best reflects the body's physiological load status. However, if you only look at the heart rate number itself without understanding the "heart rate zones" represented behind it, it is easy to ride at the wrong intensity during training, leading to accumulated fatigue, insufficient recovery, and even affecting long-term progress efficiency.
Bryton bike computers utilize Heart Rate Zones to help riders convert riding intensity into an understandable and controllable training framework. As long as you master the meaning of each zone, you can arrange endurance training, intensity training, and recovery rides with greater precision.
How Are Heart Rate Zones Calculated?
Heart rate zones are typically set based on one of the following methods:
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Maximum Heart Rate (MHR): A common estimation method is: 220 − age. This is an approximate value; actual maximum heart rate will vary due to individual fitness and training background. A more precise method is to obtain it through professional testing.
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Lactate Threshold Heart Rate (LTHR): This is approximately the average heart rate sustained during 30–60 minutes of high-intensity exercise, commonly used for more advanced endurance training analysis.
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Reminder: Different setting methods suit different users; it is recommended to adjust them periodically along with training progress.
ZONE 1 | Recovery Zone (Approx. 50–60% MHR)
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Training Goal: Promotes blood circulation, accelerates recovery, and reduces bodily load.
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Suitable Scenarios: Warm-ups and cool-downs, recovery rides after high-intensity training, and easy leisure rides.
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This zone does not pursue speed or distance; the focus is on letting the body return to a state capable of sustainable training.
ZONE 2 | Endurance Zone (Approx. 60–70% MHR)
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Training Goal: Builds an aerobic base, improving long-duration riding capacity and energy utilization efficiency.
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Suitable Scenarios: Long-distance endurance training, foundational preparation phases for century rides or island-looping trips, and steady cruise riding.
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ZONE 2 is the most important heart rate zone for endurance riders and serves as the crucial foundation for long-term progress.
ZONE 3 | Tempo Zone (Approx. 70–80% MHR)
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Training Goal: Elevates cardiorespiratory efficiency and muscle endurance, developing steady output capacity.
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Suitable Scenarios: Long-duration flat-road riding, group rides and tempo training, and simulated race pacing.
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This zone easily accumulates fatigue; it is recommended to consciously control its usage time to prevent falling into a long-term state of training at a mediocre, ambiguous intensity.
ZONE 4 | Lactate Threshold Zone (Approx. 80–90% MHR)
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Training Goal: Increases lactate tolerance, elevating the capacity for sustainable high-intensity output.
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Suitable Scenarios: Climbing training, threshold interval training, and performance breakthrough phases.
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This belongs to a high-load zone; it is recommended to pair it with sufficient recovery, and it is unsuitable for consecutive days of use.
ZONE 5 | High-Intensity Zone (Approx. 90–100% MHR)
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Training Goal: Elevates short-duration high-output capacity and the cardiorespiratory ceiling.
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Suitable Scenarios: Short-duration sprints, high-intensity intervals, and race or critical sector training.
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This zone can only be maintained for a short duration and should be paired with a complete warm-up and sufficient recovery.
Why Do Heart Rate Zones Typically Only Go up to ZONE 5?
Heart rate itself inherently possesses a physiological response delay; when a rider performs an extremely short-duration burst or an instantaneous sprint, the heart rate often cannot reflect the actual immediate output intensity in real time. Therefore, under these types of high-intensity scenarios, relying solely on heart rate as an interpretation basis easily produces errors.
Precisely because of this, heart rate zones in training applications mostly utilize ZONE 1 to ZONE 5 as the primary training zone boundaries; performances exceeding this intensity are more suited to be interpreted alongside power, cadence, or speed data to be closer to the actual output state.
At extremely high intensities, besides the response delay, heart rate also exhibits clear individual variances. Therefore, ZONE 6 and ZONE 7 are not used for structured training; instead, they serve as intensity prompts and safety references. When performing high-intensity or explosive training, it is recommended to use power or speed data as the primary basis, while heart rate serves as an auxiliary observation indicator.
ZONE 6 | Extremely High Heart Rate Zone (Approx. 100–105% MHR)
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Orientation Explanation (Critical): ZONE 6 is not used for structured training; instead, it is used to denote "entering a state of extremely high physiological stress for a short duration."
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Applicable Significance: Identifying whether over-loading has occurred, serving as a risk reminder for high-intensity training, and helping riders avoid staying in an excessively high heart rate zone for long durations.
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Usage Reminder: If the heart rate stays in this zone for a long duration, it is recommended to immediately reduce intensity and replenish fluids.
ZONE 7 | Extreme Heart Rate Zone (Higher than Personal Normal Max Heart Rate)
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Orientation Explanation (Must be clearly written): ZONE 7 does not belong to a training zone; instead, it displays an "extreme state that exceeds the normal heart rate range."
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Applicable Significance: Serving as a safety warning reference, helping identify abnormal physiological reactions or sensor measurement errors, and reminding riders to pay attention to their physical condition.
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Usage Reminder: It is not recommended to deliberately chase this zone, nor should it serve as a training goal.
Summary | Use the Right Heart Rate Zones for Efficient Training
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ZONE 1–2: Building foundations, promoting recovery
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ZONE 3–4: Elevating efficiency, breaking through performances
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ZONE 5: Training ceiling, short-duration high-intensity stimulation
When you understand the true meaning of heart rate zones, what the bike computer displays is no longer just numbers, but an important tool that assists you in controlling intensity, avoiding overtraining, and progressing steadily.