A Simple Breakdown of Heart Rate Zones and What They’re Actually For

Most training mistakes come from misunderstanding intensity. People either train too easy to progress or too hard to recover. Heart rate zones give context to effort and explain why some sessions move the needle and others don’t.

Zone 1 (50–60%)

Warm-ups and recovery. Doesn’t build fitness, but lets you train more often without burning out.

Zone 2 (60–70%)

The aerobic base. This is where endurance is built. Feels easy, works slowly, but compounds over time.

Zone 3 (70–80%)

“Grey zone.” Improves aerobic strength, but too much of it leads to fatigue without much payoff.

Zone 4 (80–90%)

Threshold work. Hard but controlled. Raises the pace you can sustain for longer efforts.

Zone 5 (90–100%)

Max effort. Short intervals only. Improves speed and VO₂ max, high recovery cost.

The key thing most apps miss is that time in each zone isn’t equal. Ten minutes near max heart rate creates far more physiological stress than ten easy minutes. That’s why we’re building MOTRA around heart-rate-verified effort, so hard sessions are recognised