A Study on the Effect of Contact Pressure during Physical Activity on Photoplethysmographic Heart Rate Measurements.pdf (1.19 MB)

A study on the effect of contact pressure during physical activity on photoplethysmographic heart rate measurements

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journal contribution
posted on 09.09.2020, 09:53 by Francesco Scardulla, Leonardo D’Acquisto, Raffaele Colombarini, Sijung Hu, Salvatore Pasta, Diego Bellavia
Heart rate (HR) as an important physiological indicator could properly describe global subject’s physical status. Photoplethysmographic (PPG) sensors are catching on in field of wearable sensors, combining the advantages in costs, weight and size. Nevertheless, accuracy in HR readings is unreliable specifically during physical activity. Among several identified sources that affect PPG recording, contact pressure (CP) between the PPG sensor and skin greatly influences the signals. Methods: In this study, the accuracy of HR measurements of a PPG sensor at different CP was investigated when compared with a commercial ECG-based chest strap used as a test control, with the aim of determining the optimal CP to produce a reliable signal during physical activity. Seventeen subjects were enrolled for the study to perform a physical activity at three different rates repeated at three different contact pressures of the PPG-based wristband. Results: The results show that the CP of 54 mmHg provides the most accurate outcome with a Pearson correlation coefficient ranging from 0.81 to 0.95 and a mean average percentage error ranging from 3.8% to 2.4%, based on the physical activity rate. Conclusion: Authors found that changes in the CP have greater effects on PPG-HR signal quality than those deriving from the intensity of the physical activity and specifically, the individual best CP for each subject provided reliable HR measurements even for a high intensity of physical exercise with a Bland–Altman plot within ±11 bpm. Although future studies on a larger cohort of subjects are still needed, this study could contribute a profitable indication to enhance accuracy of PPG-based wearable devices.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Sensors

Volume

20

Issue

18

Publisher

MDPI AG

Version

VoR (Version of Record)

Rights holder

© The Authors

Publisher statement

This is an Open Access Article. It is published by MDPI under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

03/09/2020

Publication date

2020-09-05

Copyright date

2020

eISSN

1424-8220

Language

en

Depositor

Dr Sijung Hu. Deposit date: 7 September 2020

Article number

5052