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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Physio-logging
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1498399
This article is part of the Research Topic Physio-logging in Humans: Recent Advances and Limitations in Wearable Devices for Biomedical Applications View all 4 articles

Towards a Hyperventilation Detection System in Freediving: A Proof of Concept Using Force Sensor Technology

Provisionally accepted
Frank Pernett Frank Pernett 1*Eric Robert Mulder Eric Robert Mulder 1Filip Johansson Filip Johansson 1Arne Sieber Arne Sieber 1,2Roberto Bermudez Roberto Bermudez 3Markus Lossner Markus Lossner 4Erika Schagatay Erika Schagatay 1,5
  • 1 Mid Sweden University, Sundsvall, Västernorrland, Sweden
  • 2 Oxygen Scientific GmbH, Graz, Austria
  • 3 Sensing Systems Corporation, Darthmouth, United States
  • 4 Independent hardware and software engineer, Georgia, United States
  • 5 Swedish Winter Sports Research Centre, Faculty of Human Sciences, Mid Sweden University, Östersund, Sweden

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

    Background and aims: Hyperventilation before breath-hold diving (freediving) is widely accepted to be a risk factor for hypoxic syncope or blackout (BO), but there is no practical way to address it before dives. This study explores the feasibility of using a force sensor to predict end-tidal carbon dioxide (PETCO2) to assess hyperventilation in freedivers. Methods and results: Twenty-one freedivers volunteered to participate during two national competitions. The divers were instructed to breathe normally and to perform three dry apneas of 1, 2, and 3-minute duration at 2 min intervals in a sitting position. Before and after apneas PETCO2 was recorded. The signal from the force sensor, attached to a chest belt, was used to record the frequency and amplitude of the chest movements, and the product of those values in the 60 seconds before apnea was used to predict PETCO2. The mean PETCO2 was below 35 mmHg before all apneas. The mean amplitude of the signal from the force sensor increased from apnea 1 to apnea 3 (p < 0.001) while the respiratory rate was similar (NS). The product of the respiratory rate and amplitude from the force sensor explained 34% of the variability of the PETCO2 in the third apnea. Conclusion: This study shows that a force sensor can estimate hyperventilation before static apnea, which is a basis for further research. More studies are needed to confirm its effectiveness in preventing issues. Freedivers may hyperventilate without noticing it, and such a system could improve awareness of this condition. Additional underwater tests are essential to determine if this system can enhance safety in freediving.

    Keywords: Tidal Volume, breath-hold, Apnea, Blackout, Wearable Technology

    Received: 18 Sep 2024; Accepted: 29 Nov 2024.

    Copyright: © 2024 Pernett, Mulder, Johansson, Sieber, Bermudez, Lossner and Schagatay. 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: Frank Pernett, Mid Sweden University, Sundsvall, 851 70, Västernorrland, Sweden

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.