Paperdoi:10.1098/rsos.221382

Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG

Venue listed2023Added Oct 30, 2026

Authors: Radhagayathri Udhayakumar, Saifur Rahman, Dilpreet Buxi, Vaughan G. Macefield, Tye Dawood, Nicholas Mellor, Chandan Karmakar (Deakin; Philia Labs; Baker Heart and Diabetes Institute)

Royal Society Open Science 10(8):221382

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Open code

TL;DR

Thirty-two healthy adults wore a four-wavelength wrist PPG (green, blue, infrared, red) during a 10-minute baseline followed by isometric handgrip and cold pressor tasks. Amplitude-based complexity features were compared between rest and stress. Total sample entropy of the PPG amplitude detected sympathetic change on all wavelengths, while Petrosian fractal dimension and average sample entropy reached AUC of 0.8 or more only on infrared and red light.

Form factor: wrist

Abstract

The onset of stress triggers sympathetic arousal (SA), which causes detectable changes to physiological parameters such as heart rate, blood pressure, dilation of the pupils and sweat release. The objective quantification of SA has tremendous potential to prevent and manage psychological disorders. Photoplethysmography (PPG), a non-invasive method to measure skin blood flow changes, has been used to estimate SA indirectly. However, the impact of various wavelengths of the PPG signal has not been investigated for estimating SA. In this study, we explore the feasibility of using various statistical and nonlinear features derived from peak-to-peak (AC) values of PPG signals of different wavelengths (green, blue, infrared and red) to estimate stress-induced changes in SA and compare their performances. The impact of two physical stressors: and Hand Grip are studied on 32 healthy individuals. Linear (Mean, s.d.) and nonlinear (Katz, Petrosian, Higuchi, SampEn, TotalSampEn) features are extracted from the PPG signal’s AC amplitudes to identify the onset, continuation and recovery phases of those stressors. The results show that the nonlinear features are the most promising in detecting stress-induced sympathetic activity. TotalSampEn feature was capable of detecting stress-induced changes in SA for all wavelengths, whereas other features (Petrosian, AvgSampEn) are significant (AUC ≥ 0.8) only for IR and Red wavelengths. The outcomes of this study can be used to make device design decisions as well as develop stress detection algorithms.

Verbatim from the publisher's DOI record (opens in a new tab) · Publisher licence: https://royalsociety.org/journals/ethics-policies/data-sharing-mining/

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Tasks & signals

Signals

PPG

Keywords

Sympathetic ArousalMulti WavelengthPPG AmplitudePPG ComplexityCold PressorHandgripOpen DataPhilia Labs

How it works

Wavelengths: green, blue, infrared, red

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Udhayakumar, R., Rahman, S., Buxi, D., Macefield, V. G., Dawood, T., Mellor, N., & Karmakar, C. (2023). Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG. Royal Society Open Science, 10(8), 221382. https://doi.org/10.1098/rsos.221382

Udhayakumar, Radhagayathri, Saifur Rahman, Dilpreet Buxi, Vaughan G. Macefield, Tye Dawood, Nicholas Mellor, and Chandan Karmakar. 2023. "Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG." Royal Society Open Science 10 (8): 221382. https://doi.org/10.1098/rsos.221382.

Udhayakumar, R., Rahman, S., Buxi, D., Macefield, V. G., Dawood, T., Mellor, N. and Karmakar, C. (2023) 'Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG', Royal Society Open Science, 10(8), p. 221382. doi: 10.1098/rsos.221382.

Udhayakumar, Radhagayathri, et al. "Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG." Royal Society Open Science, vol. 10, no. 8, 2023, p. 221382. https://doi.org/10.1098/rsos.221382.

R. Udhayakumar et al., "Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG," Royal Society Open Science, vol. 10, no. 8, p. 221382, 2023, doi: 10.1098/rsos.221382.

@article{udhayakumar2023measurement,
  title         = {{Measurement of stress-induced sympathetic nervous activity using multi-wavelength PPG}},
  author        = {Udhayakumar, Radhagayathri and Rahman, Saifur and Buxi, Dilpreet and Macefield, Vaughan G. and Dawood, Tye and Mellor, Nicholas and Karmakar, Chandan},
  year          = {2023},
  journal       = {Royal Society Open Science},
  volume        = {10},
  number        = {8},
  pages         = {221382},
  doi           = {10.1098/rsos.221382}
}

Oct 30, 2026Added to the ChatPPG research hub