Longstanding vs Apple Watch Cardio Fitness
Apple Watch estimates VO₂max from outdoor walks, runs and hikes and classifies it against your age and sex. Longstanding reads that estimate as one of ten tests, and tells you the line you need for 85.
Checked against Apple Watch Cardio Fitness’s own pages on
The short answer
They are not rivals; one feeds the other. Apple Watch gives you one number, an estimated VO₂max, placed in a level for your age and sex. Longstanding can read that number from Apple Health and uses it as one test of ten, alongside strength, balance and stair-climbing tests the watch cannot do, each against its own norms and against the line you need to be on today for the things you want to do at 85. If VO₂max is all you want to follow, the watch does it on its own.
What Apple Watch Cardio Fitness is
Cardio Fitness is Apple’s name for the VO₂max estimate on Apple Watch. Apple’s support page says the watch “supports a VO2 max range of 14–65 mL/kg/min” and records an estimate during Outdoor Walk, Outdoor Run and Hiking workouts; indoor workouts do not count. It needs at least 24 hours of wear, several qualifying workouts and passive measurements before the first estimate.
The estimate accounts for age, sex, weight, height and medications that may affect heart rate, and Apple notes that conditions or medications that limit heart rate may overestimate it. In the Health app you can compare your level with others of your age and sex (classifications are for people 20 or older), and the watch sends a notification if your level is low for your age and sex and keeps sending them if it stays low.
Side by side
| Longstanding | Apple Watch Cardio Fitness | |
|---|---|---|
| What it measures | Ten field tests you do yourself: single-leg stand, 5× sit-to-stand, floor sit-and-rise, grip, dead hang, push-ups, farmer carry, VO₂max, zone 2 minutes and a four-flight stair climb. | One estimate: VO₂max, from heart and motion sensors during outdoor walks, runs and hikes. |
| How often | A baseline, then a re-test every quarter. Nothing is measured in between. | Passively, whenever you do a qualifying outdoor workout. |
| Reference | Each result is a percentile against a named published table for your age and sex, labelled estimated where no clinical table exists, and read against the line you need today for your age-85 goal. | Levels by age and sex in the Health app, for people 20 and over. Apple’s page does not name the source table. |
| Accuracy | Field tests are what they are: a stopwatch time, a count, a distance. Their limits are stated on each test page. | Apple’s own validation reports a mean error of about 1.4 ± 4.7 mL/kg/min; independent labs have found it reads about 6 mL/kg/min low on average. Any one reading can be off by a band or two. |
| Where the data lives | On your phone, with an optional iCloud or Google backup. No account and no server for your results. | In Apple Health on your iPhone, under Apple’s privacy terms. |
| What you need | A timer, a chair, a wall, a bar, two weights and a staircase. A grip dynamometer for one test. A watch is optional, for VO₂max and zone 2. | Apple Watch Series 3 or later and an iPhone. |
| Cost shape | The baseline is free. One purchase, or a yearly one, unlocks re-tests, backcast lines and history. | Included with the watch. |
| The age-85 question | The point of the app: every test has a line for 85, worked backwards to today. | Not something the feature describes. It classifies you against people your age now. |
The big difference
Cardio Fitness answers “how fit is my heart and lungs compared with people my age?”. Longstanding answers a different question: “am I on the line I need to be on today to still climb stairs, get off the floor and carry the shopping at 85?”. That needs strength, balance and getting-up tests a wrist sensor cannot see, and it needs a target that is about your future, not your peers.
The two fit together. With Apple Health linked, the app reads your latest Cardio Fitness value as its VO₂max test, scores it against the Cooper Institute table, and says in words that it is a watch estimate. Because independent tests find the watch reads low on average, the app tells you so rather than hiding it behind a percentile.
Where Apple Watch Cardio Fitness is the better choice
If what you want is a continuous, effortless trend in aerobic fitness, Cardio Fitness is it: no protocol, no stopwatch, a reading after most outdoor walks and runs, and a warning when it drops into the low range for your age. For people who will never do a field test, that is worth more than a better test they do not do.
Longstanding is not for you if
You want a wearable to measure things for you. Longstanding measures nothing by itself; you do the tests, every quarter, with a timer and a chair.
The research behind this page
- Apple’s own validation reports a mean VO₂max error of +1.4 ± 4.7 mL/kg/min, against a projected reference
- Independent lab tests find Apple Watch underestimates VO₂max by about 6 mL/kg/min
- Watch VO₂max estimates are right on average, but any one reading can be off by about ±10 mL/kg/min
- The Cooper Clinic VO₂max norms are predicted from treadmill time, and run well above measured values at older ages
Everything on this page about the other product was read off its own pages on the date shown. Prices are not listed, because they change and a stale one would mislead.