Central and Peripheral Thermal Signatures of Brain-Derived Fatigue during Unilateral Resistance Exercise: A Preliminary Study.

David Perpetuini,Damiano Formenti,Pierpaolo Iodice,Giampietro Alberti,Athos Trecroci,Giovanni Michielon,Arcangelo Merla,Chiara Filippini,Antonio Maria Chiarelli,Daniela Cardone

doi:10.3390/biology11020322

David Perpetuini, Damiano Formenti + Show 8 more

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https://doi.org/10.3390/biology11020322

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Abstract

Simple SummaryFatigue is considered a brain-derived emotion that could impact performance during the execution of physical exercises. Infrared thermography is a valuable technique able to measure the psychophysiological state associated with emotions in a contactless manner. The aim of the study is to test the capability of infrared thermography to evaluate the central and peripheral physiological effect of fatigue through facial skin and muscle temperature modulations collected during the execution of a unilateral resistance exercise of the lower limb. Both time- and frequency-domain analyses were performed on the temperature time course of the face and limbs. Particularly, significant correlations between features extracted from the thermal signals and the perceived exertion were found. These findings confirmed the ability of thermal imaging to detect both peripheral and central effects of fatigue in response to physical exercises. These results could foster the employment of infrared thermography to monitor the psychophysiological state of the athletes during training. The possibility to calibrate the training load in accordance with the psychophysiological conditions could improve the performance of the athletes during the training process and competitions.Infrared thermography (IRT) allows to evaluate the psychophysiological state associated with emotions from facial temperature modulations. As fatigue is a brain-derived emotion, it is possible to hypothesize that facial temperature could provide information regarding the fatigue related to exercise. The aim of this study was to investigate the capability of IRT to assess the central and peripheral physiological effect of fatigue by measuring facial skin and muscle temperature modulations in response to a unilateral knee extension exercise until exhaustion. Rate of perceived exertion (RPE) was recorded at the end of the exercise. Both time- (∆TROI: pre–post exercise temperature variation) and frequency-domain (∆PSD: pre–post exercise power spectral density variation of specific frequency bands) analyses were performed to extract features from regions of interest (ROIs) positioned on the exercised and nonexercised leg, nose tip, and corrugator. The ANOVA-RM revealed a significant difference between ∆TROI (F(1.41,9.81) = 15.14; p = 0.0018), and between ∆PSD of myogenic (F(1.34,9.39) = 15.20; p = 0.0021) and neurogenic bands (F(1.75,12.26) = 9.96; p = 0.0034) of different ROIs. Moreover, significant correlations between thermal features and RPE were found. These findings suggest that IRT could assess both peripheral and central responses to physical exercise. Its applicability in monitoring the psychophysiological responses to exercise should be further explored

Highlights

Infrared thermography (IRT) is a technology able to measure superficial temperatures in a contactless manner [1]
The findings of the present study demonstrate the capabilities of IRT to assess physical fatigue during a unilateral resistance exercise
Differences in temperature variations were found between different regions of interest (ROIs), revealing the potentiality of thermal imaging to discriminate physiological processes underlying the perception of fatigue

Summary

Introduction

Infrared thermography (IRT) is a technology able to measure superficial temperatures in a contactless manner [1]. This technique has been demonstrated to be informative of the psychophysiological state of the subject by detecting thermal modulations usually extracted from responsive regions (e.g., nose tip, corrugator, perioral regions) [2], allowing us to identify stress, anxiety, emotions, and fatigue [3–7]. Excess heat should be transported from the core to the skin and transferred to the environment [15]. During exercise, heat is transferred from muscle to blood and subsequently to the body core, favouring an increase in the venous return and the cardiac output. The ability to modulate skin blood flow, and superficial temperature, constitutes a powerful defence mechanism against hyperthermia [15]

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