Published in

Nature Research, npj Digital Medicine, 1(4), 2021

DOI: 10.1038/s41746-021-00531-3

Links

Tools

Export citation

Search in Google Scholar

Temporal convolutional networks predict dynamic oxygen uptake response from wearable sensors across exercise intensities

Journal article published in 2021 by Robert Amelard, Eric T. Hedge ORCID, Richard L. Hughson ORCID
This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

Full text: Download

Green circle
Preprint: archiving allowed
Red circle
Postprint: archiving forbidden
Green circle
Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

AbstractOxygen consumption ($\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 ) provides established clinical and physiological indicators of cardiorespiratory function and exercise capacity. However, $\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 monitoring is largely limited to specialized laboratory settings, making its widespread monitoring elusive. Here we investigate temporal prediction of $\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 from wearable sensors during cycle ergometer exercise using a temporal convolutional network (TCN). Cardiorespiratory signals were acquired from a smart shirt with integrated textile sensors alongside ground-truth $\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 from a metabolic system on 22 young healthy adults. Participants performed one ramp-incremental and three pseudorandom binary sequence exercise protocols to assess a range of $\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 dynamics. A TCN model was developed using causal convolutions across an effective history length to model the time-dependent nature of $\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 . Optimal history length was determined through minimum validation loss across hyperparameter values. The best performing model encoded 218 s history length (TCN-VO2 A), with 187, 97, and 76 s yielding <3% deviation from the optimal validation loss. TCN-VO2 A showed strong prediction accuracy (mean, 95% CI) across all exercise intensities (−22 ml min1, [−262, 218]), spanning transitions from low–moderate (−23 ml min1, [−250, 204]), low–high (14 ml min1, [−252, 280]), ventilatory threshold–high (−49 ml min1, [−274, 176]), and maximal (−32 ml min1, [−261, 197]) exercise. Second-by-second classification of physical activity across 16,090 s of predicted $\dot{\,{{\mbox{V}}}}{{{\mbox{O}}}}_{2}$ V ̇ O 2 was able to discern between vigorous, moderate, and light activity with high accuracy (94.1%). This system enables quantitative aerobic activity monitoring in non-laboratory settings, when combined with tidal volume and heart rate reserve calibration, across a range of exercise intensities using wearable sensors for monitoring exercise prescription adherence and personal fitness.