Heart Rate Zones

Heart Rate Zones Definition

Bands of effort, from very easy through to flat out, based on percentages of your maximum heart rate.

Generally, heart rate zones are worked out as percentage bands between 0 and your maximum heart rate.

Zone 3 being 60-70% of max heartrate, zone 2 being 50-60% for example.

HR zones are generally useful for classifying effort levels, more time in higher heart rate zones will generally indicate a higher level of effort.

While most watches default to calculating zones from 0 to max heartrate, you can set watches up to calculate them differently.

For example, basing HR zones on Heart Rate Reserve (HRR) will instead calculate based from your resting heart rate to maximum heartrate - avoiding the common problem of you getting into zone 2 on slightly fast walks.

Should I only run in zone 2?

No. This is a modern running myth. The idea for mostly zone 2 running came from how elites train. They do indeed do most of their runs at an easy, zone 2 pace.

The issue is, you're not an elite runner and you don't do the high level of distance that they do. An elite running 100+ miles per week has to run mostly easy or their body will fall apart.

If you're new to running and especially if you're only running 3 or less times a week, then only running in zone 2 won't make much of a difference unless you're prone to injuries or just prefer it.

Zone 2 isn't some special zone where you gain extra fitness, it's just a good proxy for easy, non-impactful runs that you can do more of without hurting yourself. The real fitness comes from simply running more over a long period of time.