Accuracy And Reliability Of Commercial Wrist-Worn Pulse Oximeter During Normobaric Hypoxia Exposure Under Resting Conditions

Purpose: The present study analyzed peripheral blood oxygen saturation (SpO2) and heart rate (HR) measurements taken on the Garmin fenix (R) 5X Plus watch, comparing them to measurements taken on a standard medical-grade pulse oximeter during normobaric hypoxia exposure under resting conditions.Methods: Thirteen women (mean +/- SD: Age 20 +/- 1 years, height 165 +/- 5 cm, mass, 67 +/- 9 kg) and ten men (mean +/- SD: Age 21 +/- 3 years, height 177 +/- 6 cm, mass 78 +/- 11 kg) sat inside a customized environmental chamber while the fraction of inspired oxygen (FIO2) was adjusted to simulate altitudes of 12,000; 10,000; 8,000; 6,000; and 900 ft. The novel commercial device (Garmin fenix (R)) and a medical-grade pulse oximeter (Nonin (R) 7500) were used to measure S(p)O(2)and HR in triplicate at each simulated altitude. Bland-Altman analyses were used to assess differences between methods.Results: Bland-Altman analysis indicated 3.3% bias for S(p)O(2)measurements taken on the Garmin fenix (R) at 12,000 ft of simulated altitude (limits of agreement: -1.9-8.6%). Mean differences in S(p)O(2)measurements were smaller at the remaining simulated altitudes, where bias measurements ranged from 0.7% to 0.8%. The Garmin fenix (R) also underestimated heart rate, but those discrepancies were minimal (bias measurements at all simulated altitude exposures were < 1.0 bpm).Conclusions: With the exception of readings taken at 12,000 ft of simulated altitude, the Garmin fenix (R) exhibits minimal overestimation of S(p)O(2)and minimal underestimation of HR during simulated altitude exposure. These data suggest the Garmin fenix (R) watch may be a viable method to monitor S(p)O(2)and HR under most ambient environmental conditions.