Author(s): ALBLOOSHI, E., DAAB, W., MARQUES, E.A., NASSIS, G.P., Institution: UNIVERSITY OF KALBA, Country: UNITED ARAB EMIRATES, Abstract-ID: 1210

INTRODUCTION:
Wearable devices that use photoplethysmography (PPG) are widely used among athletes and fitness enthusiasts. It seems that only a few of them have been tested for their accuracy (validity) and reliability (1). The aim of this study was to examine the validity and reliability of two commercially available devices that use the PPG technology to monitor HR.
METHODS:
Twelve males, physically active (age: 23.7±5.5 years; mean±SD) performed a familiarization session in the laboratory (24.2±1.4 °C) and two identical exercise trials on a stationary bike (Monark LC6, Sweden). During each trial, they performed three 5-min bouts, separated by 5-min rest, at their age-predicted 50%, 60% and 70% of maximum HR. HR was assessed with the same unit of each brand which were: a chest-worn HR monitor (Polar H10, Finland), previously tested for validity and served as the criterion device (2), a wrist-worn (Whoop Life, USA) and an arm-worn HR monitor (Coros, USA). The placement of the devices was as per the manufacturer’s guidelines. Validity was assessed with absolute error, mean absolute percentage error (MAPE), mean bias and 95% Limits of Agreement (LoA) between the tested devices and the chest-worn device. Reliability was assessed with the 95% prediction interval (PI) and ICC.
RESULTS:
Depending on the exercise intensity, absolute error and MAPE ranged between 1.7 bpm and 2.5 bpm and 1.4% and 2.7% for the wrist-worn and between 1.4 bpm and 1.9 bpm and 0.5% and 1.9%, respectively, for the arm-worn device. The wrist-worn device showed small mean biases (range: −0.5 bpm to 1.3 bpm) and relatively wide LoA (range: −7.8 bpm to +8.6 bpm). The mean biases for the arm-worn device ranged between -1.4 bpm and 0.7 bpm and the LoA ranged between -6.7 bpm and +3.8 bpm. ICCs were 0.98 for the chest-worn, 0.87 for the wrist-worn and 0.97 for the arm-worn device. The 95% CI ranged between -6.0 bpm and +7.9 bpm for the chest-worn, -18.2 bpm and +15.3 bpm for the wrist-worn and -8.0 bpm and +9.0 bpm for the arm-worn device.
CONCLUSION:
The preliminary results of this ongoing study indicate that both the wrist- and arm-worn devices seem to demonstrate acceptable validity. However, reliability varied between devices and seemed to be influenced by the exercise intensity with 95% PI getting narrower as the intensity increased. These findings should be interpreted taking into consideration the limitation of the study, namely the small sample size.
(1) Doherty et al. Sports Med 2024;54:2907-2926
(2) Etiwy et al. Cardiovasc Diagn Ther 2019;9:262-271.