Assessing Accuracy of Smartwatch-based Estimation of Maximum Oxygen Consumption Using Different Watches

Authors

Chelsea Seifert, Angelo State UniversityFollow
Jenna O'Dell, Angelo State UniversityFollow
Aaron Canham, Angelo State UniversityFollow
Shae Harris, Angelo State UniversityFollow
Shelly Weise, Angelo State UniversityFollow

Abstract

Maximal oxygen consumption (VO_2max) is a predictor of overall health and a key measure of cardiovascular fitness and aerobic capacity. As wearable technology advances, smartwatches are increasingly used to track cardiovascular health metrics. PURPOSE: The purpose of this study was to evaluate the validity and reliability of maximal oxygen consumption estimates from two leading smartwatches. METHODS: 15 participants (11M, 4F), aged 19-29 (23.8±3.2) years, were recruited and met inclusion criteria for the study. VO_2max for all participants was determined in a controlled laboratory environment using a metabolic gas analyzer. Subjects completed a graded exercise test on a treadmill until reaching subjective exhaustion. This value was then compared with the estimated VO_2max values from two smartwatch devices (Watch A, Watch B), calculated while wearing the watches for at least 3 consecutive days and measured directly after an outdoor run. The watches were synced between runs and returned after the study period. Baseline descriptive data calculations were performed. Reliability was measured using Intraclass Correlation Coefficient (ICC). Bland-Altman analyses were utilized to explore VO_2max values. RESULTS: Measured VO_2max in the lab setting was significantly lower than the predicted VO_2max (mL·min^-1·kg^-1) from Watch A (mean 45.28±6.51 vs. mean 48.68±7.03) (p=.041) and Watch B (mean 47.69±8.64 vs. mean 52.83±5.83) (p=.041) with a medium effect size. ICC average measures (2,2) for Watch A (0.836, p=.003) and for Watch B (0.856, p=.001) suggested good reliability for VO_2max estimates for both watches and the lab setting measurements. Bland-Altman analyses confirmed overestimation and consistent agreement. CONCLUSION: Both smartwatches tended to overestimate VO_2max compared to lab measurements but exhibited good reliability across trials. Either device may be acceptable for recreational users to track VO_2max outside of a laboratory setting. However, healthcare professionals should be aware of estimation limitations when prescribing intensity for cardiorespiratory fitness.

Recommended Citation

Seifert, Chelsea; O'Dell, Jenna; Canham, Aaron; Harris, Shae; and Weise, Shelly (2025) "Assessing Accuracy of Smartwatch-based Estimation of Maximum Oxygen Consumption Using Different Watches," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 17, Article 1.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss17/1