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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Autonomic Neuroscience
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1421676

Pupil light reflex in young elite athletes: autonomic nervous system activity and viscoelastic properties

Provisionally accepted
Cyril J. GIOVANNANGELI Cyril J. GIOVANNANGELI 1*Fabio Borrani Fabio Borrani 2Olivier Broussouloux Olivier Broussouloux 3Olivier Maurelli Olivier Maurelli 1Laurent Schmitt Laurent Schmitt 4Robin B. Candau Robin B. Candau 1
  • 1 INRA UMR Dynamique Musculaire et Métabolisme, Montpellier, France
  • 2 Université de Lausanne, Lausanne, Vaud, Switzerland
  • 3 University of Corsica Pascal Paoli, Corte, Corsica, France
  • 4 Centre National de Ski Nordique et de Moyenne Montagne (CNSNMM), Prémanon, France

The final, formatted version of the article will be published soon.

    The pupil light reflex (photomotor reflex) has a duration of 3.5 seconds and is a highly reproducible measurement. Conventionally, the autonomic nervous system (ANS) activity evaluated by this reflex does not consider the viscoelasticity of the iris muscles. This study aims to detect differences in reflex autonomic activity in a supine position with parameters derived from the Kelvin-Voigt viscoelastic model in two distinct groups of elite athletes formed using a dendrogram analysis based on basal autonomic activity assessed with heart rate variability. Heart rate variability was measured, and the photomotor reflex was modeled. The model showed a high degree of adjustment to the photomotor reflex (r²=0.99±0.01). The impulse 3, an indicator of reflex sympathetic activity, revealed a significantly higher activity (ρ≤0.05) in the [sympa/para] + group compared to the [sympa/para] -group. This result was further supported by a greater relative total redilation amplitude (ρ≤0.05) and a shorter duration of 75% redilation (ρ≤0.01). Finally, the relative total redilation amplitude exhibited a significant correlation with the linear stiffness constant (ρ≤0.001) and the maximum redilation speed with restoring force (ρ≤0.001). These results indicate that (i) the photomotor reflex can detect an alteration of the reflex autonomic activity specific to each of the two branches of the ANS (ii) the viscoelastic properties of the iris muscles play a significant role in the energy storage-restitution mechanisms during the photomotor reflex. This approach could allow athletes to benefit from reduced time spent in the analysis of ANS activity, potentially making it an almost daily and automated process.

    Keywords: photomotor reflex1, sympathetic nervous system2, parasympathetic nervous system3, smooth muscle stiffness4, monitoring5 photomotor reflex, Sympathetic Nervous System, Parasympathetic Nervous System, Smooth Muscle Stiffness

    Received: 22 Apr 2024; Accepted: 18 Jul 2024.

    Copyright: © 2024 GIOVANNANGELI, Borrani, Broussouloux, Maurelli, Schmitt and Candau. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Cyril J. GIOVANNANGELI, INRA UMR Dynamique Musculaire et Métabolisme, Montpellier, France

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