Target Health Rate Zone

"Exercise in your target zone" is standard advice, but the zone is personal: it is a band of heart rates derived from your age, below which training is very light and above which it becomes hard to sustain. This calculator works out your estimated maximum heart rate and the training zones beneath it, so a heart-rate monitor reading or a manual pulse check tells you something useful mid-workout.

Quick Answer

Estimated maximum heart rate = 220 − your age. The general target zone for aerobic exercise is 50–85% of that maximum: moderate intensity at roughly 50–70%, vigorous intensity at roughly 70–85%.

Why Zones Are Built From Maximum Heart Rate

Maximum heart rate falls steadily with age — not because the heart weakens, but because the electrical pacing of the heart and its response to adrenaline change over a lifetime. Subtracting age from 220 is a population average fitted to that decline, and expressing exercise intensity as a percentage of the maximum lets one framework describe a gentle walk for a 60-year-old and a hard run for a 25-year-old in the same language.

Trainers usually slice the percentages into five zones. Zone 1 (50–60%) is recovery pace — conversational, sustainable for hours. Zone 2 (60–70%) is the aerobic base zone where most endurance volume is built and fat contributes a large share of fuel. Zone 3 (70–80%) is tempo territory, comfortably hard. Zone 4 (80–90%) is threshold work, sustainable only in intervals for most people. Zone 5 (90–100%) is maximal, measured in minutes at most. Public-health guidance for general fitness centres on the moderate-to-vigorous span — about 50–85% — rather than any single zone.

Measuring Your Heart Rate, and a Smarter Formula

A zone is only useful if the number you compare with it is honest. To take a manual pulse, place two fingers on the radial artery inside the wrist (not your thumb, which has its own pulse), count for 15 seconds and multiply by four — and count the first beat as zero, or you systematically add up to four phantom beats per minute. Chest-strap monitors measure the heart's electrical signal directly and are the accuracy reference; wrist watches estimate from blood flow under the skin and can lag behind sudden changes or mistake your step rhythm for your pulse during running.

For a more personal target than the plain percentage method, trainers often use the Karvonen formula, which factors in resting heart rate: target = resting HR + percentage × (maximum HR − resting HR). Take the 35-year-old from the example, with a maximum of 185 and a resting rate of 65: the reserve is 120 beats, and a 70% effort means 65 + 84 = 149 bpm — noticeably higher than the 130 bpm the simple percentage method gives for the same nominal intensity, because Karvonen credits the fitness that a low resting rate implies. Resting heart rate itself, typically 60–100 bpm in adults and lower in the endurance-trained, is worth knowing before choosing between the two methods.

How to Use This Target Heart Rate Zone Calculator

1. Enter your age in years.
2. Read your estimated maximum heart rate.
3. Note the zone boundaries calculated as percentages of that maximum.
4. Pick the zone that matches your session's purpose — base building, tempo or intervals.
5. During exercise, compare your measured heart rate (monitor, watch or a 15-second pulse count multiplied by 4) with the zone.
6. Adjust pace to stay in the intended band, remembering that heart rate lags effort changes by several seconds.

Worked Example: A 35-Year-Old

For a 35-year-old, estimated maximum heart rate is 220 − 35 = 185 beats per minute. The general target zone of 50–85% therefore runs from 93 to 157 bpm: moderate work at 93–130 bpm, vigorous work at 130–157 bpm. Broken into the five training zones, the same maximum gives:

• Zone 1 (50–60%): 93–111 bpm
• Zone 2 (60–70%): 111–130 bpm
• Zone 3 (70–80%): 130–148 bpm
• Zone 4 (80–90%): 148–166 bpm
• Zone 5 (90–100%): 166–185 bpm

Zones Are Sport-Specific

A less obvious wrinkle: maximum heart rate is not identical across sports. Running usually produces the highest values because it recruits the most muscle mass upright; cycling maxima typically land a few beats lower, and swimming lower still — often around ten beats below running, thanks to the horizontal position, the cooling effect of water and the smaller muscle mass driving the effort. A zone table built from a running test will therefore overstate the targets for the pool, leaving a swimmer chasing numbers their heart will not reach at the intended effort. Serious multi-sport athletes test and set zones separately for each discipline. For general fitness the differences are small enough to ignore, but if one sport consistently feels harder than its zone says it should, a sport-specific maximum is the first explanation to check.

How Much to Trust the 220 Minus Age Formula

It is an average, and averages conceal spread: for any individual, the true maximum can sit 10–12 beats above or below the estimate. A refined formula, 208 − (0.7 × age), tracks measured data slightly better — it gives 183.5 for our 35-year-old — but it is still an estimate. If you have done a genuine maximal-effort field test under supervision, use that measured number instead.

Medication changes the picture completely. Beta blockers and some other heart medicines deliberately blunt heart rate, making percentage zones meaningless; people taking them are usually directed to perceived effort (the talk test — moderate effort still allows short sentences, vigorous effort only a few words) instead. Heat, dehydration, altitude, illness and accumulated fatigue also push heart rate above what the same pace costs on a cool, rested day, so treat the zones as a guide to effort, not a command. Finally, wrist-based optical monitors can lag or lock onto your step cadence during intervals; a chest strap is the more trustworthy source when the numbers look strange.

These zones are general-information fitness estimates, not medical guidance. Anyone with a heart condition, symptoms during exercise, or medication affecting heart rate should agree exercise targets with their doctor before using zone-based training.

Training Partners for This Calculator

Heart-rate zones decide how hard to work; the calories burned calculator estimates what a session at that effort costs energetically, and the pace calculator translates target effort into running speeds. All three sit in the health calculators collection.