Heart Rate Zone Training for Runners: A Practical Guide

Heart rate zone training means running at a target range of heart rates instead of a target pace, so each run does the job it is meant to do. Most runners use five zones, set either as percentages of maximum heart rate or of heart rate reserve (maximum minus resting). The biggest practical benefit for most people is keeping easy runs truly easy, so the hard sessions can be hard.

Why train by heart rate instead of pace?

Pace tells you how fast you are moving; heart rate tells you how hard your body is working to do it. The same pace can feel very different on a hot day, up a hill, into a headwind, after a bad night or when you are coming down with something. Heart rate adjusts for those conditions automatically, which helps you avoid turning an easy day into a moderate one without noticing.

Heart rate has limits too. It responds slowly at the start of an effort, so it lags behind during short intervals, and it drifts upward during long runs as you warm up and lose fluid. Many runners use heart rate for easy and steady running and pace or effort for short, fast intervals.

Step 1: estimate your maximum heart rate

Zones are anchored to your maximum heart rate. You can estimate it with a formula:

• 220 minus age - the simplest and best known. A 40-year-old gets 180 bpm.
• 208 minus (0.7 x age) - the Tanaka formula, often a little closer for older adults. A 40-year-old gets 180 bpm; a 60-year-old gets 166 bpm.

Any formula is an estimate for a population; your real maximum could be 10 or more beats higher or lower. If you have run hard races recently, the highest heart rate you have reliably seen in the closing minutes is a useful reality check. Do not attempt an all-out maximum test without being used to hard exercise, and speak with a doctor first if you have a heart condition, high blood pressure, or other health concerns. For the details, read how to estimate your maximum heart rate.

Step 2: choose a method to set your zones

Method A: percentage of maximum heart rate

Multiply your maximum by each percentage. This is simple and widely used.

Method B: heart rate reserve (the Karvonen method)

This method takes your resting heart rate into account, which tends to suit fitter runners with low resting rates. The formula is:

Target heart rate = ((maximum - resting) x intensity) + resting

Example: maximum 185, resting 55. Heart rate reserve is 130. For 70 percent intensity: (130 x 0.70) + 55 = 146 bpm.

Both methods give reasonable starting points. Neither is precise for every individual, so adjust based on how sessions feel over a few weeks.

The five heart rate zones and what each is for

Example for a maximum of 180 bpm: Zone 2 is about 108 to 126 bpm and Zone 4 about 144 to 162 bpm. Different coaches and devices draw the lines in slightly different places, so do not worry if your watch shows boundaries a few beats off from these.

How much time should you spend in each zone?

Research on how successful endurance athletes train has found a consistent pattern: most training - often around 80 percent of sessions - is done at low intensity, with a smaller share at high intensity and relatively little in the middle. Recreational runners do not need to copy elite volumes, but the principle transfers well:

• Make most runs easy (Zones 1 and 2).
• Add one or two harder sessions a week (Zones 4 and 5) once you have a base.
• Be wary of doing every run at a "medium" effort in Zone 3, which is a common habit.

A sample week

• Monday - rest or easy walk
• Tuesday - 40 minutes easy (Zone 2)
• Wednesday - warm-up, then 3 x 8 minutes in Zone 4 with 3 minutes easy between, cool-down
• Thursday - 30 to 40 minutes easy, or rest
• Friday - rest
• Saturday - 30 minutes easy with 6 short, relaxed strides
• Sunday - long run in Zone 2, increasing gradually week to week

Adjust the volume to your experience. Increase total running gradually rather than in big jumps.

Common pitfalls

• Trusting a formula too much. If Zone 2 feels like a struggle or Zone 4 feels easy, your estimated maximum is probably off. Adjust it.
• Cardiac drift. On long or hot runs your heart rate climbs even at the same pace. Slow down a little to stay in your zone, or accept a gradual rise late in the run.
• Short intervals. Heart rate takes a minute or more to catch up. Use pace or effort for short repeats.
• Sensor glitches. Wrist heart rate can read oddly during the first minutes, in cold weather or with a loose band. A sudden spike that does not match how you feel is usually a reading error. Wear the watch snugly above the wrist bone.
• Ignoring the bigger picture. Poor sleep, stress, heat and illness all raise heart rate. On those days, run easier or rest.

When to stop

Stop running and seek medical help if you have chest pain or pressure, feel faint or dizzy, become unusually short of breath, or notice a heartbeat that feels irregular or much faster than the effort should cause. If you have a heart condition or take medication that affects heart rate, ask your doctor what intensity is right for you - zones based on age formulas may not apply.

Reviewing your runs in FitRest

FitRest shows each workout saved to Apple Health with a breakdown of time in heart rate zones and a route map with replay, so you can see whether an easy run really stayed easy. Cardio Load and Training Rhythm show how your training builds up over weeks, and Cardio Recovery shows how quickly your heart rate comes down in the minute after a workout. See the workouts feature page.

Sources

• American Heart Association - Target Heart Rates Chart
• Tanaka H, Monahan KD, Seals DR - Age-predicted maximal heart rate revisited (Journal of the American College of Cardiology, 2001)
• Seiler S - What is best practice for training intensity and duration distribution in endurance athletes? (International Journal of Sports Physiology and Performance, 2010)
• Buchheit M - Monitoring training status with HR measures: do all roads lead to Rome? (Frontiers in Physiology, 2014)