Consumer Wearable-based Vo2max Estimates Compared To Metabolic Cart During A Training Intervention

Tracking health and fitness information is more accessible and comprehensive due to the prevalence of wearable technology. Many devices provide estimations of VO2max, a key determinant of cardiovascular fitness and aerobic performance. PURPOSE: To compare the validity and reliability of wearable-based (Garmin & Polar) methods of estimating VO2max to a gold-standard measurement (indirect calorimetry). METHODS: 47 active-duty Air Force personnel (n = 47; males = 34, females = 13) completed a treadmill VO2max test before and after a 12-week training intervention. Before completing the lab test, participants completed the supine orthostatic Polar Fitness Test on the Polar GritX Pro watch to estimate VO2max. Within 5 days of the lab test, participants completed a 1.5-mile Cooper Test while wearing a Garmin Fenix 6 watch and a Polar H10 chest strap to generate a VO2max estimate. RESULTS: Mean absolute percentage error (MAPE) and Lin’s Concordance (CCC) were assessed for both Garmin (MAPE: 9.4%; CCC: 0.63) and Polar (MAPE: 12.0%; CCC: 0.46). After training, there was a significant increase in VO2max as measured by the metabolic cart (3.19 ml/kg/min ± 1.96; p < 0.01), but no significant changes were detected by Garmin (-0.13 ml/kg/min ± 0.18; p = 0.74) or Polar (0.19 ml/kg/min ± 0.73; p = 0.71). Likewise, when participants who experienced at least an 8% increase in VO2max (p < 0.01) were analyzed separately, neither Garmin nor Polar demonstrated any changes in VO2max estimate. CONCLUSIONS: VO2max estimates from both Garmin and Polar were not accurate at single time points and did not detect significant changes in actual VO2max over time.