# Apple Watch VO2 max not updating: what to check Source: https://wellhero.co/apple-watch-vo2-max-not-updating/ Language: en-US [Home](https://wellhero.co/)[Blog](https://wellhero.co/blog/)Cardio Fitness not updating By [Wellhero](https://wellhero.co/author/wellhero/) · Published November 11, 2026 If your Apple Watch VO2 max is not updating, check the date of the latest Cardio Fitness record in Apple Health first. A saved workout does not guarantee a new estimate. Apple needs a suitable outdoor session and usable sensor data; the number in another app may also come from a different source. Start with the individual records, especially if the summary chart looks unchanged. ![Two women in sportswear walking along a paved path in a sunny park](https://wellhero.co/assets/apple-watch-vo2-max-not-updating/outdoor-walk-pexels-7266743.jpg) Illustrative photo by [Sarah Chai](https://www.pexels.com/@sarah-chai/) on [Pexels](https://www.pexels.com/photo/fit-sportswomen-walking-in-sunny-autumn-park-7266743/), used under the [Pexels License](https://www.pexels.com/license/). - [Check the latest saved record](https://wellhero.co/apple-watch-vo2-max-not-updating/#records) - [Check which workouts can produce an estimate](https://wellhero.co/apple-watch-vo2-max-not-updating/#eligible) - [Review the route and sensor readings](https://wellhero.co/apple-watch-vo2-max-not-updating/#conditions) - [If another app has a different result](https://wellhero.co/apple-watch-vo2-max-not-updating/#apps) - [What to do if it still does not update](https://wellhero.co/apple-watch-vo2-max-not-updating/#next) ## Check the latest saved record Open Health on your iPhone and find Heart, then Cardio Fitness. Scroll to Show All Data and inspect the latest entry's date and source. Data Sources & Access lists the devices and apps contributing to that category. Apple's [Health data guide](https://support.apple.com/en-us/108779) explains where to find these controls. - If the newest entry predates your recent workouts, Apple Health has no newer saved estimate to display. - If there is a recent entry with the same number, recording has continued. An unchanged value is a different question from missing data. - If Health has a new entry but your fitness app shows an old one, investigate that app's data access and source selection. Write down the date before changing anything. A monthly graph or an app's rounded headline number can make it difficult to see whether a new individual record arrived. Comparing entries shows whether you are investigating a missing measurement or an unchanged result. ## Only certain workouts generate Apple's estimate Apple lists Outdoor Walk, Outdoor Run and Hiking in its Workout app as supported activities. Indoor workouts do not qualify. A treadmill session can therefore appear in your workout history without adding Cardio Fitness data. The same applies to expecting Apple's estimate from a cycling or strength session. See Apple's [Cardio Fitness guide](https://support.apple.com/en-au/108790). Select the workout type that matches what you actually do. Do not label an indoor run as an outdoor run to try to force a reading. ### If you have never had a reading Apple says an initial estimate can require at least 24 hours of wear, several supported outdoor workouts and passive measurements. Complete Cardio Fitness setup in Health if prompted, and check your personal details. The estimate considers age, sex, height, weight and medications that affect heart rate. That initial waiting period does not explain every later interruption. If readings used to arrive and have stopped, compare the last recorded session with recent ones: workout type, route, recorder and available pulse data. ## A completed outdoor workout can still lack a VO₂ max result VO₂ max describes the maximum amount of oxygen your body can use during exercise. Apple Watch estimates it from your response to activity. Apple's [measurement documentation](https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/vo2max) describes relatively flat ground, adequate GPS and heart rate signals, and sufficient effort as conditions for generating a sample. A steep hike or a walk with poor GPS reception can be a valid workout while providing unsuitable data for this particular estimate. For your next usual outdoor session, choose a familiar, relatively level route with a clear view of the sky, if practical. There is no need to exercise to exhaustion: Apple says its estimate does not require you to reach your maximum heart rate. Check the saved route and pulse trace afterward. A detailed graph alone cannot prove that every condition for VO₂ max estimation was met, but any gaps are worth investigating first. ### Check recording settings before resetting anything In the iPhone Watch app, open Privacy and confirm Heart Rate is enabled. Wear the watch snugly on top of your wrist, with comfortable skin contact. Apple's [measurement guidance](https://support.apple.com/en-us/105002) explains how fit, cold skin and some tattoos can affect pulse readings. Review Health Details in the Watch app if your personal information is out of date. If the trace has missing sections, use our [workout heart rate gap checklist](https://wellhero.co/apple-watch-heart-rate-gaps/). It covers the recording and power settings in more detail. Avoid deleting Health history or resetting all calibration data as a first response to a missing estimate. ## If another app has a different result Check whether the app displays a saved Apple Health value or calculates its own estimate. Also compare the source and time period shown. A fresh number in a different app does not, by itself, establish that Apple Watch wrote a new Cardio Fitness record. For an app that reads Health data, review its permissions in Health under your profile, then Apps. Check the relevant category and the app's own source settings. If Health has the record and the app still does not show it after syncing, send that app's support team the record date and source. If Health has no record, changing a downstream app's permission will not create Apple's missing measurement. In Wellhero, you can review a recorded workout's pulse chart, time in heart rate zones and recording coverage. Those details help you understand the available session data while investigating a missing Cardio Fitness entry. The [Wellhero workout analysis guide](https://wellhero.co/features/workout-analysis-with-apple-watch/#workout-data) shows where to find them. ## What to do if it still does not update Keep a short record of the affected sessions: date, workout type, recording app, route conditions and whether the pulse trace has gaps. Include your watch model and software versions, plus the date of the last Cardio Fitness entry, when contacting Apple Support. This distinguishes a first estimate that never appeared from an established history that stopped updating. Do not enter a guessed VO₂ max value to make the chart move. A manual record would document the number you entered, not demonstrate that the watch had resumed estimating it. A missing entry tells you that you lack a new estimate; it cannot show whether your fitness improved or declined. If the number you are looking at is Cardio Recovery, that measures the fall in pulse after exercise and needs a different check. See [what to review when Apple Watch cardio recovery looks low](https://wellhero.co/apple-watch-cardio-recovery-low/).