How to update Apple Watch Max Heart Rate for zone calculation?

You can update the zones.

See View Heart Rate Zones on Apple Watch - Apple Support (JO)

To the best of my knowledge, that is not an option.

You can let Apple know it's something you'd like to see here:

Product Feedback - Apple

My understanding is that the Max Heart Rate calculation uses one of some fairly standard forumulas. For example:

• Traditional Formula (Haskell & Fox): 220 - age (Easy to use, but can be less accurate for very fit or older adults).
• Tanaka Formula: 208 - (0.7 × age) (Often more accurate for adults over 40 and active individuals).
• Nes Formula: 211 - (0.64 × age) (Frequently recommended for active or fit individuals). 

I don't think wearables generally base it on your workout history.

I know I can update them manually by entering the specific beats per minute for each of the five zones, which is what I mentioned in my post.

What I am looking for is a way for the watch to automatically update my Max Heart Rate based on my actual workout data, or at least let me enter a custom Max Heart Rate and have the watch calculate the zones from there.

According to Siri AI:

Other wearable brands do offer this feature. Both Garmin and WHOOP automatically update your maximum heart rate based on observed data from your workouts.

Here is how a few other major brands handle maximum heart rate:

• Garmin: Compatible Garmin devices feature an "Auto Detection" setting. If the watch detects a sustained heart rate during an activity that is higher than your currently set maximum, it will automatically update your profile and adjust your zones accordingly.

• WHOOP: WHOOP starts with an age-based estimate but refines your maximum heart rate over time using observed workout data. It also allows you to manually override the maximum heart rate if you have a lab-tested value, while still automatically calculating your zones using the Heart Rate Reserve method.

• Polar: While Polar devices typically default to an age-based formula, they allow you to manually input a known maximum heart rate in your profile, which the system then uses to automatically scale your zones.

KennethGlobal wrote:

According to Siri AI:

Other wearable brands do offer this feature. Both Garmin and WHOOP automatically update your maximum heart rate based on observed data from your workouts.

Here is how a few other major brands handle maximum heart rate:

Garmin:• Compatible Garmin devices feature an "Auto Detection" setting. If the watch detects a sustained heart rate during an activity that is higher than your currently set maximum, it will automatically update your profile and adjust your zones accordingly.

WHOOP:• WHOOP starts with an age-based estimate but refines your maximum heart rate over time using observed workout data. It also allows you to manually override the maximum heart rate if you have a lab-tested value, while still automatically calculating your zones using the Heart Rate Reserve method.

Polar:• While Polar devices typically default to an age-based formula, they allow you to manually input a known maximum heart rate in your profile, which the system then uses to automatically scale your zones.

Good to know! So you should definitely submit the suggestion to Apple.

KennethGlobal wrote:

Thank you for the suggestion which I have submitted to Apple.

I'll have to check out how it works on the Whoop. Just please don't ask why I have one of those in addition to an Apple Watch. My technology habit is embarrassing enough as it is.

Thank you for the suggestion which I have submitted to Apple.