Heart-rate zones for short workouts

Heart-rate zones split your effort into five bands, each a percentage of your maximum heart rate. In a short bodyweight workout you'll usually spend most of your time in the middle zones, 3 and 4, and that's fine. You don't need to live in zone 5 to get fitter, and you don't need perfect zones to use them well.

This guide explains what the zones are, how your maximum is estimated and why that estimate can be off, what a typical 10 to 20 minute home workout looks like in zones, and how to use them without letting a number run your workout.

What heart-rate zones are

Most apps and watches use five zones, each a slice of your maximum heart rate. The exact cut-offs vary between apps, but a common set looks like this:

So for someone with a maximum of 185 beats per minute, zone 3 runs from about 130 to 148, and zone 5 starts at about 167.

How your maximum is estimated

Your true maximum heart rate can only be measured with an all-out test, which most people never do. So apps estimate it from your age. The oldest and most common formula is 220 minus your age, which gives 185 for a 35-year-old. A newer formula from a large 2001 analysis, 208 minus 0.7 times your age, gives about 184 at 35 and is a little more accurate for older people (Tanaka and colleagues, 2001).

Either way, it's an average. Two people of the same age can have maximums ten or more beats apart, so your zones could be shifted up or down for you. Some medications, such as beta blockers, also lower your heart rate, which makes age-based zones much less useful. That's why zones are best treated as a guide, and why it helps to check them against how hard a workout actually feels.

Apple Watch calculates its own five zones as a percentage of your maximum heart rate, personalised from your health data, and it needs your date of birth in the Health app. You can also set the zones yourself on the watch, under Settings, Workout, Heart Rate Zones. Different apps use different methods, so the same workout can look slightly different in each.

What a short workout looks like in zones

Bodyweight circuits don't hold one steady heart rate the way a run can. Expect a pattern like this:

• The first minute or two in zones 1 and 2. Your heart rate takes a while to catch up with the work, which is one reason a gentle start is worth it.
• A climb through the session. Each round starts from a slightly higher heart rate than the last, because 20 or 30 seconds of rest isn't enough to come all the way down.
• Peaks on the whole-body moves. Jumping jacks, burpees, mountain climbers and squat jumps push your heart rate highest. Slow strength moves and holds, like planks, glute bridges and wall sits, raise it less, even when your muscles are burning.
• Small dips during rests. These show up as a sawtooth if you look at the graph.

A typical 12 to 20 minute session ends up with most of its time in zones 3 and 4, with a little in zone 5 if it includes jumps. A quiet, jump-free strength workout often sits more in zones 2 and 3. That doesn't make it a worse workout: it's building strength, which heart rate doesn't measure well.

How to use your zones

• Look at the time in each zone afterwards, not during. In a 30-second exercise your heart rate lags behind your effort, so watching it live mostly tells you about the exercise before.
• Compare like with like. The same workout a few weeks apart is the most useful comparison. If it now feels easier and spends less time in zone 5 for the same work, you've got fitter.
• Want more cardio? Shorten the rests, add a round, or swap a hold for a whole-body move. Your time in zones 3 to 5 goes up.
• Want an easier day? Lengthen the rests and choose slower moves. Mostly zones 2 and 3 is a fine recovery session.
• Trust how you feel, too. Rate your effort from 1 to 10, or use the talk test from the table. If the numbers and your body disagree, your body is usually right, and your zones may need adjusting.

One caution: zone 5 isn't a target. Hard efforts have their place, but very high heart rates aren't needed to make progress, especially when you're starting out. If you have a heart condition or take medication that affects your heart rate, ask your doctor which heart rates are right for you.

Heart-rate zones in Streaks Workout

When you work out with an Apple Watch, Streaks Workout records your heart rate during the workout and shows your live heart rate as you go. When you finish, it shows how long you spent in each of five zones, along with your average heart rate, on your iPhone or on the watch, and you can look back at them in your workout history. The workout is saved to Apple Health with your heart rate and energy.

The app's zones use the bands in the table above and the 220 minus age formula, with your age taken from your date of birth in the Health app. If you haven't set a date of birth there, add it so your zones fit you.

Sources

1. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology. 2001;37(1):153–156. PubMed
2. Apple. View heart rate zones on Apple Watch. Apple Watch User Guide