Garmin VO₂max has done better in small studies, but the evidence is thin
Is Garmin VO₂max accurate?
The finding
Mean absolute percentage error was 7.05% and Lin’s concordance 0.73, which met the authors’ criteria for acceptable accuracy (CCC above 0.7, MAPE under 10%).
- Authors
- Carrier B, Marten Chaves S, Navalta JW
- Published
- Sensors 25(1):275 · 2025
- Evidence
- Read in the primary source; numbers checked.
- Source
- doi.org/10.3390/s25010275
How it was studied
19 adults wearing a Garmin Fēnix 6, compared with 30-second averaged lab data.
The numbers
An earlier study of five wrist devices (Passler et al., 2019) reported errors above 10% for all of them except a Garmin Forerunner 920XT for VO₂max; that figure was not checked against the paper.
What it does not show
Fewer than 20 people, and results are specific to each device and firmware version.
What Longstanding does with it
Same advice as for any watch: use the same source every quarter and read the trend.