How Samsung Galaxy Watch Calculates Your Max Heart Rate
Samsung starts at 220 − age, now layers Galaxy AI personal zones on top, and keeps the setting per exercise type rather than once for everything.
Samsung Galaxy Watch estimates your maximum heart rate with 220 − age, then offers to replace it in two ways: automatically, using personal intensity zones derived from your cardiovascular data, or manually, with a number you type in. The unusual part is where that setting lives. On a Galaxy Watch, max heart rate is stored per exercise type, not once for your whole profile.
The per-sport setting nobody finds
Open Samsung Health, pick an exercise type, open its settings through the three-dot menu, and you will find a heart rate zones section showing the current maximum with a choice between automatic and custom.
Set it for running and you have set it for running. Swimming, cycling and everything else keep their own values, and each has to be changed on its own.
This is genuinely the right design, badly signposted. Your running maximum usually sits several beats above your cycling maximum, because more muscle mass is working, and a single global number is wrong for at least one of your sports. Polar offers the same thing through sport profiles. Most brands do not offer it at all.
The cost is that an untouched Galaxy Watch is running an age formula separately in every activity you do, and fixing one does not fix the rest.
What 220 − age costs you
The formula carries an individual error of roughly ±10 to 12 bpm, and it is biased: too high for young athletes, too low for older ones. At 20 it predicts 200 where Gellish predicts 193. At 60 it predicts 160 where Gellish predicts 165. Garmin, COROS and WHOOP have all moved off it for exactly this reason.
最大心拍数
185bpm
| ゾーン | 範囲 | 鍛えられるもの |
|---|---|---|
| Z1 | リカバリー 93–111 bpm | アクティブリカバリーとウォームアップ。疲労を加えずに血流を促進します。 非常に楽、RPE 1〜2。普通に会話でき、ほとんど息が上がりません。 |
| Z2 | エンデュランス 111–130 bpm | 有酸素的な土台、脂質酸化、毛細血管密度を養う、日々の基盤となるゾーンです。 快適、RPE 3〜4。完全な文章で話せます。 |
| Z3 | テンポ 130–148 bpm | 有酸素能力と筋持久力。「やや強い」定常的な運動です。 頑張っている、RPE 5〜6。短い文章のみ。 |
| Z4 | スレッショルド 148–167 bpm | 乳酸性作業閾値、持続可能なレースペースの上限です。 きつい、RPE 7〜8。一度に数語のみ。 |
| Z5 | VO₂max 167–185 bpm | 短く強いインターバルで最大有酸素パワーとVO₂maxを高めます。 非常にきつい〜最大、RPE 9〜10。会話不可。 |
Z1 · リカバリー. アクティブリカバリーとウォームアップ。疲労を加えずに血流を促進します。 非常に楽、RPE 1〜2。普通に会話でき、ほとんど息が上がりません。
Z2 · エンデュランス. 有酸素的な土台、脂質酸化、毛細血管密度を養う、日々の基盤となるゾーンです。 快適、RPE 3〜4。完全な文章で話せます。
Z3 · テンポ. 有酸素能力と筋持久力。「やや強い」定常的な運動です。 頑張っている、RPE 5〜6。短い文章のみ。
Z4 · スレッショルド. 乳酸性作業閾値、持続可能なレースペースの上限です。 きつい、RPE 7〜8。一度に数語のみ。
Z5 · VO₂max. 短く強いインターバルで最大有酸素パワーとVO₂maxを高めます。 非常にきつい〜最大、RPE 9〜10。会話不可。
- ゾーンは最大心拍数の単純な割合です（Z1 50〜60%からZ5 90〜100%まで）。設定は簡単ですが、HRmaxが正確であることが前提です。
- 心拍は労力に1〜3分遅れて反応し、暑さや脱水で上方にドリフトします（「カーディアックドリフト」）。短く強い運動は感覚で判断してください。
パーソナライズされた結果のPDFと、いつでも再表示できるQRコード付き。
Enter a tested maximum to see where your boundaries actually belong before you type them into the watch.
Automatic zones, and the reason to be careful
Newer Galaxy Watches will calculate five personal intensity zones from your cardiovascular data rather than from the age formula. In principle that is an improvement, for the same reason WHOOP's learned maximum is: a number observed from your own training beats a population average.
In practice, be sceptical until you have checked it. Every learned maximum has the same weakness, which is that optical wrist sensors throw artefact spikes at high intensity and the model cannot tell a spike from a genuine peak.
There is also a practical wrinkle worth knowing: users have repeatedly reported custom maximum values being ignored or reset after software updates. Whatever you set, check it again after your watch updates rather than assuming it held.
How to get it right
Test the number. Build to hard over 10 to 15 minutes, finish with an all-out 60 to 90 second effort, uphill if you can, take the highest reading off a chest strap, repeat within two weeks and keep the higher figure. Not for anyone with cardiac risk or new to hard training. Full protocol in finding your maximum heart rate.
Set it per exercise type, in each activity you actually train.
Consider a better anchor. Percentage-of-maximum says nothing about fitness. If you have a tested threshold heart rate, LTHR zones place the boundaries better, and Karvonen is the middle option if you know your resting heart rate.
FAQ
What formula does Samsung Galaxy Watch use for max heart rate? 220 − age by default, with an option to switch to automatically calculated personal zones or a custom value.
How do I change max heart rate on a Galaxy Watch? In Samsung Health, open the exercise type, use the three-dot menu to reach settings, find heart rate zones, and choose custom.
Why do I have to set my max heart rate for every sport? Samsung stores it per exercise type. It is more accurate if you use it, since running and cycling maximums differ, but it means one change does not carry over.
My custom max heart rate keeps resetting. Why? Users have reported custom values being ignored or lost after updates. Re-check the setting after your watch updates.
Are Galaxy Watch heart rate zones accurate? Only as accurate as the maximum underneath them. The default is an age estimate. Test yours and enter it per sport.
Other brands
- Garmin uses Tanaka and auto-raises HRmax from peaks.
- Apple Watch publishes no formula at all.
- Fitbit uses 220 − age with reserve-based zones.
- WHOOP seeds with Gellish and learns from your data.
Sources
- Samsung Community on setting max heart rate per exercise
- Samsung Community on custom heart rate zones
- Tanaka, Monahan & Seals (2001), the 208 − 0.7 × age formula
- Gellish et al. (2007), the 207 − 0.7 × age formula
Cover photo by Dinkun Chen, CC BY-SA 4.0, via Wikimedia Commons.
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