What each zone is for

Training zones are six bands of effort. This page is what the bands are for, which is the same for everybody; the numbers themselves are per runner, and Taper puts yours on the Zones screen in Profile once it has enough of your running to work them out.

Z1 · Recovery

Running that helps you get through the rest of the week. It builds very little on its own, and that is what it is for.

How it feels. Easy enough to be slightly dull. You could talk without thinking about it, and you finish fresher than you started.

Watch out for. Very few people run this slowly outdoors unless they decide to beforehand. If your recovery days keep landing a zone up, they are easy days, and your easy days are then doing two jobs.

Z2 · Easy

Aerobic base, and most of your week by time. The adaptations here take months to build and then hold for years.

How it feels. Full sentences without pausing for breath. Steady rather than slow.

Watch out for. The commonest way to get slower is to run this slightly too hard every day for months. When your heart rate says Z3 and your pace says Z2, Taper marks the run as pushed rather than easy.

Z3 · Steady

Honest aerobic work: long runs with some intent, marathon-effort blocks, the middle of a progression run.

How it feels. Comfortably hard. Short sentences. You know you are working and you could keep going for a long time.

Watch out for. This is where an easy run drifts to on a good day. Once or twice a week that is training. Every day it is the grey zone: too hard to recover from, too easy to be the session.

Z4 · Threshold

The band your one-hour race effort sits in. Deliberately wide: it runs from hard steady up through your lactate threshold.

How it feels. A few words at a time. You could hold it for about an hour if you had to, and it stops being pleasant well before that.

Watch out for. Wide means the top and the bottom of it are different sessions, so your plan asks for a named pace inside this zone rather than anywhere in the range.

Z5 · VO2max

Aerobic power. Repetitions of roughly three to five minutes, where you spend real time near your ceiling.

How it feels. One word at a time. Your breathing is the loudest thing you can hear, and the last minute of each rep is the session.

Watch out for. Heart rate lags the effort by the better part of a minute, so on short reps its average never catches up with what you actually did. Taper grades reps that short on pace instead.

Z6 · Maximal

Speed and mechanics: strides, hill sprints, short repetitions. Neuromuscular work rather than aerobic work.

How it feels. No talking. Each rep should finish before it starts to hurt properly.

Watch out for. The recovery between reps is part of the session and not a formality. Cut it and this becomes a long Z5 session, which trains something else and costs more to recover from.

Where the numbers come from

A runner's threshold pace, threshold heart rate and maximum heart rate come from their own running, measured by Taper from what they have already run. Every boundary between the zones is one of those multiplied by a fixed ratio, and the ratios are the same for everyone unless you have set your own in Profile. They are a sensible way to divide up your training. They are not a measurement of you.

Paces are shown to the nearest five seconds. They are worked out from one anchor effort, so the second they would otherwise print is precision the estimate does not have.

Your plan asks for easy runs at a pace that lands in Z3 and recovery runs at one that lands in Z2, which reads oddly next to a zone named easy. The zone names describe efforts; a prescribed pace is one point inside a zone, not the whole band.

Your own screen says how well each of your two anchors is known, and what stands behind it: Profile, then Zones.