Commercial Smart Watches and Heart Rate Monitors: A Concurrent Validity Analysis.

ABSTRACT: Montalvo, S, Martinez, A, Arias, S, Lozano, A, Gonzalez, MP, Dietze-Hermosa, MS, Boyea, BL, and Dorgo, S. Smartwatches and commercial heart rate monitors: a concurrent validity analysis. J Strength Cond Res 37(9): 1802-1808, 2023-The purpose of this study was to explore the concurrent validity of 2 commercial smartwatches (Apple Watch Series 6 and 7) against a clinical criterion device (12-lead electrocardiogram [ECG]) and a field criterion device (Polar H-10) during exercise. Twenty-four male collegiate football players and 20 recreationally active young adults (10 men and 10 women) were recruited and participated in a treadmill-based exercise session. The testing protocol included 3 minutes of standing still (resting), then walking at low intensity, jogging at a moderate intensity, running at a high intensity, and postexercise recovery. The intraclass correlation (ICC 2,k ), and Bland-Altman plot analyses showed a good validity of the Apple Watch Series 6 and Series 7 with increased error (bias) as jogging and running speed increased in the football and recreational athletes. The Apple Watch Series 6 and 7 are highly valid smartwatches at rest and different exercise intensities, with validity decreasing with increased running speed. Strength and conditioning professionals and athletes can confidently use the Apple Watch Series 6 and 7 when tracking heart rate; however, caution must be taken when running at moderate or higher speeds. The Polar H-10 can surrogate a clinical ECG for practical applications.

Differences in Blood Flow Patterns and Endothelial Shear Stress at the Carotid Artery Using Different Exercise Modalities and Intensities.

Endothelial dysfunction is the first pathophysiological step of atherosclerosis, which is responsible for 90% of strokes. Exercise programs aim to reduce the risk of developing stroke; however, the majority of the beneficial factors of exercise are still unknown. Endothelial shear stress (ESS) is associated with endothelial homeostasis. Unfortunately, ESS has not been characterized during different exercise modalities and intensities in the carotid artery. Therefore, the purpose of this study was to determine exercise-induced blood flow patterns in the carotid artery. Fourteen apparently healthy young adults (males = 7, females = 7) were recruited for this repeated measures study design. Participants completed maximal oxygen consumption (VO2max) tests on a Treadmill, Cycle-ergometer, and Arm-ergometer, and 1-repetition maximum (1RM) tests of the Squat, Bench Press (Bench), and Biceps Curl (Biceps) on separate days. Thereafter, participants performed each exercise at 3 different exercise intensities (low, moderate, high) while a real-time ultrasound image and blood flow of the carotid artery was obtained. Blood flow patterns were assessed by estimating ESS via Womersley's estimation and turbulence via Reynold's number (Re). Data were analyzed using a linear mixed-effects model. Pairwise comparisons with Holm-Bonferroni correction were conducted with Hedge's g effect size to determine the magnitude of the difference. There was a main effect of intensity, exercise modality, and intensity * exercise modality interaction on both ESS (p < 0.001). Treadmill at a high intensity yielded the greatest ESS when compared to the other exercise modalities and intensities, while Bench Press and Biceps curls yielded the least ESS. All exercise intensities across all modalities resulted in turbulent blood flow. Clinicians must take into consideration how different exercise modalities and intensities affect ESS and Re of the carotid artery.