# What are my five heart rate zones?

Works out five heart rate training zones, the ACSM exercise intensity classes, from age (and optionally resting heart rate by the Karvonen method), and which zone a heart rate is in.

- Page: https://www.acalculator.org/health/heart-rate-zone-calculator
- JSON spec: https://www.acalculator.org/health/heart-rate-zone-calculator.json
- Version: 0a8dac0cfbe0

## Default answer

Example with the default inputs (Age 35, Maximum heart rate formula 220 − age): With a maximum heart rate of 185 bpm, zone 2 (light) is 105 to 117 bpm and zone 3 (moderate) is 118 to 141 bpm.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| age | Age | Your age in whole years. |
| formula | Maximum heart rate formula | How the maximum heart rate is estimated from age: 220 − age, or 208 − 0.7 × age (Tanaka). |
| max | Measured maximum heart rate | Your maximum heart rate from a test, if you know it. It replaces the age estimate. |
| rest | Resting heart rate | Your heart rate at rest, in beats per minute. With it, the zones use the heart rate reserve (Karvonen). |
| hr | Heart rate to check | A heart rate measured during exercise, in beats per minute, to see which zone it is in. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| max | Maximum heart rate | The measured maximum, or the age estimate, in beats per minute. |
| zone1 | Zone 1: Very light | The very light zone in whole beats per minute: from rest to the start of zone 2. |
| zone2 | Zone 2: Light | The light zone in whole beats per minute: 57% to 63% of the maximum, or 30% to 39% of the reserve. |
| zone3 | Zone 3: Moderate | The moderate zone in whole beats per minute: 64% to 76% of the maximum, or 40% to 59% of the reserve. |
| zone4 | Zone 4: Vigorous | The vigorous zone in whole beats per minute: 77% to 95% of the maximum, or 60% to 89% of the reserve. |
| zone5 | Zone 5: Near maximal | The near maximal zone in whole beats per minute: 96% of the maximum or 90% of the reserve, up to the maximum. |
| zoneOf | Checked heart rate is in | The zone of the heart rate to check, from the whole-number zone limits above. |
| method | Zones based on | Shares of the maximum heart rate, or of the heart rate reserve when a resting heart rate is given. |

## Method

Zone start = rest + share × (max − rest), with rest 0 and shares 57%, 64%, 77%, 96% of the maximum, or with the resting heart rate and shares 30%, 40%, 60%, 90% of the reserve (Karvonen); max = 220 − age or 208 − 0.7 × age.

## Assumptions

- The five zones are the ACSM exercise intensity classes: very light, light, moderate, vigorous, and near maximal to maximal (Garber and others, 2011).
- Each zone limit is rounded half up to a whole beat per minute; a zone ends one beat before the next one starts.
- The age formulas estimate the maximum heart rate; a measured maximum can differ by 10 beats per minute or more.
- Heart-rate medicines such as beta blockers change the response to exercise. This is not medical advice.

## Worked examples

1. age = 30, formula = fox gives max = 190, zone1 = Below 108 bpm, zone2 = 108 to 121 bpm, zone3 = 122 to 145 bpm, zone4 = 146 to 181 bpm, zone5 = 182 to 190 bpm. Source: ACSM intensity classes (Garber 2011, Table 4): 190 × 0.57 = 108.3, × 0.64 = 121.6, × 0.77 = 146.3, × 0.96 = 182.4.
2. age = 40, formula = fox, rest = 60, hr = 130 gives max = 180, zone1 = 60 to 95 bpm, zone2 = 96 to 107 bpm, zone3 = 108 to 131 bpm, zone4 = 132 to 167 bpm, zone5 = 168 to 180 bpm, zoneOf = Zone 3: moderate, method = Heart rate reserve (Karvonen). Source: ACSM %HRR classes (Garber 2011) with Karvonen 1957: 60 + 0.3 × 120 = 96, 0.4 → 108, 0.6 → 132, 0.9 → 168.
3. age = 50, formula = tanaka, hr = 150 gives max = 173, zone2 = 99 to 110 bpm, zone4 = 133 to 165 bpm, zoneOf = Zone 4: vigorous. Source: Tanaka 2001: 208 − 0.7 × 50 = 173.

## FAQ

### What are the five heart rate zones?

This calculator uses the five exercise intensity classes of the American College of Sports Medicine: very light, light, moderate, vigorous, and near maximal to maximal. As shares of the maximum heart rate they start at 57%, 64%, 77% and 96%; as shares of the heart rate reserve, at 30%, 40%, 60% and 90%.

### What is zone 2?

Here, zone 2 is the ACSM "light" class: 57% to 63% of the maximum heart rate, or 30% to 39% of the heart rate reserve. Other zone systems, such as those in some fitness watches, use different bands, so check which scale your device uses.

### What is the Karvonen method?

Karvonen and others (1957) based training heart rates on the heart rate reserve, the maximum minus the resting heart rate. A target is resting + share × reserve. Because it includes your resting heart rate, it fits fit people with low resting rates better than shares of the maximum alone.

### How do I find my maximum heart rate?

The simplest estimate is 220 − age. Tanaka and others (2001) found 208 − 0.7 × age fits adults better, especially older adults. Both are averages; your true maximum can differ by 10 beats a minute or more. A supervised exercise test measures it; enter it under More options.

### How do I measure my resting heart rate?

Count your pulse for a full minute after waking, before getting up, on a few mornings, and take the average.

### Which zone should I train in?

The ACSM advises moderate or vigorous aerobic exercise for most adults, and light exercise for people starting out. Talk to a health care provider before starting, especially if you have a heart condition or take medicine that changes your heart rate.

## Sources

- Garber CE, Blissmer B, Deschenes MR, et al. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. American College of Sports Medicine position stand. Med Sci Sports Exerc. 2011;43(7):1334-1359 (Table 4, relative intensity classes). https://doi.org/10.1249/MSS.0b013e318213fefb
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn. 1957;35(3):307-315. https://pubmed.ncbi.nlm.nih.gov/13470504/
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-156. https://doi.org/10.1016/s0735-1097(00)01054-8
- Centers for Disease Control and Prevention. Target Heart Rate and Estimated Maximum Heart Rate (220 − age; archived copy). http://web.archive.org/web/20221225180518/https://www.cdc.gov/physicalactivity/basics/measuring/heartrate.htm