TRAINING TERMS
Zone 3
The first of the App’s higher working bands; movement can be continuous or divided into bouts.
70% to below 80% of reserve
Zone 3 starts at resting heart rate + 70% of reserve and ends just below resting heart rate + 80% of reserve. The percentages refer to the gap between resting heart rate and estimated maximum, not to maximum heart rate alone.[1]
Higher work needs room in the whole session
The App considers actual training history, recent harder activity, body information and available time before selecting a higher zone. Zone 3 work can be continuous or divided into bouts. Preparation, recovery where needed, and cooldown still belong to the session.
A band is not a threshold test
This label does not identify your lactate threshold or guarantee a particular breathing pattern. Consider the session’s structure alongside your sense of effort. Crossing into Zone 3 during an activity does not by itself mean the next session should target it.
Sources & further reading
Reviewed September 14, 2026