Longstanding vs Garmin Fitness Age
Garmin turns VO₂max, resting heart rate, activity and body composition into a fitness age. Longstanding keeps the tests separate and reads each against norms and the line for 85.
Checked against Garmin Fitness Age’s own pages on
The short answer
Garmin Fitness Age compresses several watch-derived numbers into one age so you can see whether you compare well with people of your age and sex. Longstanding refuses to compress: ten separate tests, each with its own percentile and its own age-85 line, because a strong heart and a weak grip are different problems with different fixes. If you own a Garmin, the two coexist; Garmin’s VO₂max estimate can be entered as the app’s VO₂max test.
What Garmin Fitness Age is
Garmin’s manual says Fitness Age “gives you an idea of how your fitness compares with a person of the same gender”, using “your age, body mass index (BMI), resting heart rate data, and vigorous activity history”. With a Garmin Index scale, body fat percentage replaces BMI, and Garmin asks you to complete your user profile for the most accurate result. It is shown in Garmin Connect under Health Stats.
Older Garmin watches derive Fitness Age from the VO₂max estimate alone; newer ones add the inputs above. Either way, the number inherits whatever error the VO₂max estimate carries.
Side by side
| Longstanding | Garmin Fitness Age | |
|---|---|---|
| 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 age, from VO₂max, resting heart rate, vigorous activity history and BMI or body fat. |
| How often | A baseline, then a re-test every quarter. Nothing is measured in between. | Continuously, from everyday wear and outdoor activities. |
| 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. | A comparison with people of the same sex and age. The manual does not name the reference data. |
| Accuracy | Field tests measured with a stopwatch, a count or a distance; limits stated on each test page. | Garmin’s VO₂max has done better than most wearables in small studies (about 7% mean error), but the evidence is thin and the Fitness Age formula is not published. |
| Where the data lives | On your phone, with an optional iCloud or Google backup. No account and no server for your results. | In Garmin Connect, synced to Garmin’s servers. |
| 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. | A compatible Garmin watch, and a Garmin scale for the body-fat input. |
| Cost shape | The baseline is free. One purchase, or a yearly one, unlocks re-tests, backcast lines and history. | Included with the watch and the free Garmin Connect app. |
| 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. A lower fitness age means fitter than your peers now. |
The big difference
A fitness age is a comparison with your peers, folded into a single number. That is useful as motivation and useless for deciding what to train, because the inputs are hidden inside the age. Longstanding shows the inputs and nothing else: your sit-to-stand time against the reference times for your decade, your grip against the Dodds centiles, your VO₂max against the Cooper table, and for each one the line you need today for your own goal at 85.
Garmin does one thing the app does not try to do: it watches you all week. The app only knows what you did in the ten-minute quarterly session. If you want both, enter Garmin’s VO₂max estimate as the app’s VO₂max test and keep Fitness Age for the weekly glance.
Where Garmin Fitness Age is the better choice
Garmin’s VO₂max estimate is among the better-validated wearable estimates, its watches track vigorous activity without you doing anything, and Fitness Age is a single motivating number that moves when training works. For a runner or cyclist who already wears a Garmin, it costs nothing extra.
Longstanding is not for you if
You want one number and a nudge. The app gives you ten numbers and a line for each, and it only updates when you sit down and test.
The research behind this page
- Garmin VO₂max has done better in small studies, but the evidence is thin
- Watch VO₂max estimates are right on average, but any one reading can be off by about ±10 mL/kg/min
- Measured VO₂max norms (FRIEND) give medians of 48.0 and 37.6 mL/kg/min at 20–29, falling to 24.4 and 18.3 at 70–79
- 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.