@Article{info:doi/10.2196/56676,
author="Zhang, Yuankai
and Wang, Xuzhi
and Pathiravasan, Chathurangi H
and Spartano, Nicole L
and Lin, Honghuang
and Borrelli, Belinda
and Benjamin, Emelia J
and McManus, David D
and Larson, Martin G
and Vasan, Ramachandran S
and Shah, Ravi V
and Lewis, Gregory D
and Liu, Chunyu
and Murabito, Joanne M
and Nayor, Matthew",
title="Association of Smartwatch-Based Heart Rate and Physical Activity With Cardiorespiratory Fitness Measures in the Community: Cohort Study",
journal="J Med Internet Res",
year="2024",
month="Jun",
day="13",
volume="26",
pages="e56676",
keywords="mobile health; smartwatch; heart rate; physical activity; cardiorespiratory fitness; cardiopulmonary exercise testing",
abstract="Background: Resting heart rate (HR) and routine physical activity are associated with cardiorespiratory fitness levels. Commercial smartwatches permit remote HR monitoring and step count recording in real-world settings over long periods of time, but the relationship between smartwatch-measured HR and daily steps to cardiorespiratory fitness remains incompletely characterized in the community. Objective: This study aimed to examine the association of nonactive HR and daily steps measured by a smartwatch with a multidimensional fitness assessment via cardiopulmonary exercise testing (CPET) among participants in the electronic Framingham Heart Study. Methods: Electronic Framingham Heart Study participants were enrolled in a research examination (2016-2019) and provided with a study smartwatch that collected longitudinal HR and physical activity data for up to 3 years. At the same examination, the participants underwent CPET on a cycle ergometer. Multivariable linear models were used to test the association of CPET indices with nonactive HR and daily steps from the smartwatch. Results: We included 662 participants (mean age 53, SD 9 years; n=391, 59{\%} women, n=599, 91{\%} White; mean nonactive HR 73, SD 6 beats per minute) with a median of 1836 (IQR 889-3559) HR records and a median of 128 (IQR 65-227) watch-wearing days for each individual. In multivariable-adjusted models, lower nonactive HR and higher daily steps were associated with higher peak oxygen uptake (VO2), {\%} predicted peak VO2, and VO2 at the ventilatory anaerobic threshold, with false discovery rate (FDR)--adjusted P values <.001 for all. Reductions of 2.4 beats per minute in nonactive HR, or increases of nearly 1000 daily steps, corresponded to a 1.3 mL/kg/min higher peak VO2. In addition, ventilatory efficiency (VE/VCO2; FDR-adjusted P=.009), {\%} predicted maximum HR (FDR-adjusted P<.001), and systolic blood pressure-to-workload slope (FDR-adjusted P=.01) were associated with nonactive HR but not associated with daily steps. Conclusions: Our findings suggest that smartwatch-based assessments are associated with a broad array of cardiorespiratory fitness responses in the community, including measures of global fitness (peak VO2), ventilatory efficiency, and blood pressure response to exercise. Metrics captured by wearable devices offer a valuable opportunity to use extensive data on health factors and behaviors to provide a window into individual cardiovascular fitness levels. ",
issn="1438-8871",
doi="10.2196/56676",
url="https://www.jmir.org/2024/1/e56676",
url="https://doi.org/10.2196/56676",
url="http://www.ncbi.nlm.nih.gov/pubmed/38870519"
}