TRAINING TERMS

Zone 5

The App’s highest band, used selectively rather than as a goal every session should reach.

← Back to the training library

90% of reserve and above

Zone 5 starts at resting heart rate + 90% of reserve. The App classifies readings at or above that boundary in this band. This classification is not an instruction to exceed your estimated maximum or to exercise at an all-out effort.

Selected from evidence, not ambition

The App uses this band selectively, considering training history, recent harder activity, body information and available time. If selected, the session has multiple work bouts and easier recovery between them. Having more free time or seeing Zone 5 in the library does not make it the next step in your training.

The highest number is not a score

An age-based maximum is a general estimate, and medication can change the heart-rate response. A Zone 5 reading cannot certify your capacity or the benefit of a session. Judge the session by its intended work and how you respond, not by whether you reach the highest band.

Sources & further reading

Reviewed September 14, 2026