Heart Rate Zones Explained (Simply)

Your smartwatch shows "zones" but never explains them. Here’s what heart rate zones actually mean and how to use them for better cardio.

The five zones

First, estimate your max heart rate roughly as 220 minus your age (a ballpark). The zones are percentages of that:

• Zone 1 (50–60%): very easy, warm-up.
• Zone 2 (60–70%): easy, conversational — the fat-burning base.
• Zone 3 (70–80%): moderate, "comfortably hard."
• Zone 4 (80–90%): hard — raises threshold.
• Zone 5 (90–100%): all-out, short bursts (VO2 max).

How to use them

A simple, effective plan: spend most of your cardio in zone 2 (build the base, easy to recover from) and add a little zone 4–5 via intervals. You don’t need a monitor — zone 2 is simply "can talk but not sing."

Quick answers

What heart rate zone burns the most fat?

Zone 2 uses a higher percentage of fat for fuel, but total calories burned still matter most. Its real value is being easy to sustain.

How do I find my max heart rate?

A rough estimate is 220 minus your age. It varies by person, so use it as a ballpark, not an exact figure.

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