Scientific papers 2024
Back to the menu 06 - Does dopamine mediate the effects of exercise on cognition?
Authors: Marc Roig, & Jacopo Cristini Dopamine, a key neurotransmitter, is crucial for managing mood, motivation, learning, and other functions. Changes in dopamine levels are linked to cognitive decline and various mental and neurological disorders, including the cardiorespiratory system. Research, including animal studies, shows that regular cardiovascular exercise, like treadmill running, can boost dopamine levels in the brain, potentially offsetting some of these issues.
01 - Effects of oxygen-prebreathing on tissue nitrogenation in normobaric and hyperbaric conditions
Authors: Edward Tom Ashworth, Ryotaro Ogawa, David Robert Vera, Peter Lindholm Using a radioactive nitrogen isotope, this study found that pre-breathing oxygen at normobaric levels increased nitrogen levels in the blood, liver, and muscle. However, hyperbaric exposure showed no differences in tissue nitrogen levels. Both bone and muscle had higher nitrogen levels after hyperbaric exposure than normobaric exposure. The study concludes that pre-breathing oxygen eliminates nitrogen at normobaric levels, and tissues are slower to adjust their nitrogen levels under hyperbaric conditions.
BUTTON TEXT Previous page 02 - Stress biomarker changes following a series of repeated static and dynamic apneas in non-divers
Authors: Antonis Elia, Matthew J. Barlow, Matthew J. Lees, Georgios Petri, Michail E. Keramidas This study investigated the physiological effects of repeated maximal static and dynamic apnea on stress- related biomarkers in eleven healthy men. The results showed significant increases in modified albumin and myoglobin levels after the apnea interventions, particularly after dynamic apnea, indicating muscle damage. However, there were no significant changes in neuron- specific enolase or cardiac troponin, suggesting no myocardial or neuronal damage. The study concludes that dynamic apnea causes more muscle damage than static apnea, but neither causes heart or brain damage.
05 - Breathing patterns and associated cardiovascular changes in intermittently breathing animals: (Partially) correcting a semantic quagmire
Authors: Warren Burggren, Andreas Fahlman, William Milsom Many animals exhibit irregular breathing patterns with long pauses between breaths, even when their hearts are beating. This phenomenon is common among all species, from crustaceans to whales. In humans, this irregular breathing pattern is associated with health issues.Diving animals exhibit cardiovascular phenomena that lack standardized terminology, leading to confusion regarding the underlying mechanisms and pathologies. To avoid confusion and emphasize understanding of biological processes rather than terminology, more precise terms are proposed.
07 - Pulsed Hyperoxia Acts on Plasmatic Advanced Glycation End Products and Advanced Oxidation Protein Products and Modulates Mitochondrial Biogenesis in Human Peripheral Blood Mononuclear Cells: A Pilot Study on the “Normobaric Oxygen Paradox”
Authors: Costantino Balestra, Sara Baldelli, Fabio Virgili, Michele Salvagno, Simona Mrakic-Sposta, & Deborah Fratantonio The "normobaric oxygen paradox" (NOP) refers to the perceived lack of oxygen by tissues following a hyperoxic event. The authors investigate whether this phenomenon results in the production of advanced glycation end products (proteins or lipids glycated by exposure to sugars) and advanced oxidation protein products (modified proteins resulting from oxidative stress) as circulating biomarkers of oxidative stress.
08 - Occupational decompression sickness: A case report
Authors: Taylor Diederich, Allyson M. Briggs, Adrienne Malik, Bryan Beaver This article discusses the case of a 32-year-old individual who developed a mottled rash, joint pain, muscle aches, headaches, vision changes, and weakness due to decompression sickness resulting from working in a pressurized chamber at a factory. The individual underwent two sessions in a hyperbaric chamber, which completely resolved the symptoms. During the hospital stay, a patent foramen ovale was discovered. The patient was advised to avoid any further exposure to similar work environments.
09 - Risk Factors for Decompression Sickness
Authors: Elsye Fitriasari, Ni Komang Sri Dewi Untari, Nasywa Annisa Fitra Decompression sickness (DCS) is a serious health problem for divers caused by pressure changes during and after dives. It is important for all medical professionals and divers to understand the risks associated with DCS in order to promote safe diving practices. Symptoms of DCS can be rapid or gradual and may be delayed, making diagnosis difficult, especially if the diver has traveled by air after diving. Factors such as obesity, smoking, alcohol consumption, anxiety, previous injuries, and diving conditions, including cold water, duration, and depth, increase the risk of DCS.
10 - Benefit of breath­holding training on the concept of recreational freediving in healthy adults – a systematic literature review.
Authors: Muhamad Nanang Solikhin, Sumaryanti, Sulistiyono, Fauzi, Bonifacius Arbanto This review covers studies on breath-holding exercises and their health benefits, including their impact on freedive training, lung function through diaphragmatic breathing, and breath-hold performance with mental imagery training. Research also shows improvements in cardiorespiratory function for individuals with bronchial asthma, chronic obstructive pulmonary disease, and cancer, noting better pulse rates, blood pressure, respiratory function, and quality of life.
11- Review of saturation decompression procedures used in commercial diving
Authors: Jean-Pierre Imbert, Lyubisa Matity, Jean-Yves Massimelli, Philip Bryson This is a review of commercial heliox saturation decompression procedures. The scope does not include compression, storage depth or bell excursion dive procedures. The objectives are to: identify the sources of the procedures; trace their evolution; describe the current practice; and detect relevant trends.
12 - Oxygen imaging of hypoxic pockets in the mouse cerebral cortex
Authors: Felix R. M. Beinlich , Antonios Asiminas, Verena Untiet, Zuzanna Bojarowska, Virginia Plá, Björn Sigurdsson, Vincenzo Timmel, Lukas Gehrig, ichael H. Graber, Hajime Hirase, Maiken Nedergaard Consciousness disappears within seconds after blood flow to the brain stops because the brain cannot store oxygen and requires a continuous supply to function. The researchers developed a new tool to monitor oxygen levels in the brain. Using this tool, they discovered spontaneous low-oxygen areas in the brains of awake mice. This research sheds light on how the brain manages oxygen and could help understand various brain conditions and diseases.
13 - Oxy-Inflammation in Humans during Underwater Activities
Authors: Alessandra Vezzoli, Simona Mrakic-Sposta, Andrea Brizzolari, Costantino Balestra, Enrico Maria Camporesi, and Gerardo Bosco Underwater activities expose divers to conditions that can lead to oxidative stress and inflammation caused by an imbalance between reactive oxygen/nitrogen species and antioxidants. These conditions are influenced by factors such as hypoxic and hyperoxic environments, hyperbaric pressure, cold water, and different breathing gases. Divers experience physiological adaptations known as the "dive response,", which includes cardiovascular stress, increased blood pressure, peripheral vasoconstriction, altered blood gas levels, and the risk of bubble formation during decompression.
21 - In-field use of I-VED electrical impedance sensor for assessing post -dive decompression stress in humans.
Authors: Sotiris P. Evgenidis, Konstantinos Zacharias, Virginie Papadopoulou, Sigrid Theunissen, Costantino Balestra, Thodoris D. Karapantsios Impedance spectroscopy technology (I-VED),was used for the first time in humans to provide qualitative in vivo electrical impedance measurements that may contribute to the assessment of decompression stress. Compared to ultrasound imaging, the proposed method is less expensive, operator-independent, and compatible with continuous monitoring and the use of multiple probes. This study presents preliminary findings. Further calibration and validation are necessary to determine the sensitivity and specificity of I-VED.
22 - Net Heart Rate for Estimating Oxygen Consumption in Active Adults
Authors: José A. Bragada, Pedro M. Magalhães, Eric São- Pedro, Raul F. Bartolomeu, and Jorge E. Morais The study aimed to evaluate the accuracy of predicting oxygen consumption (O2) during aerobic activities using net heart rate (netHR), sex, and BMI in active adults. NetHR is calculated by subtracting the resting heart rate from the average heart rate during the activity. The study involved 156 participants, aged 18 to 81, including 52 women and 104 men, who had their netHR and net oxygen intake (netVO2) measured.
23 - Oxidative Stress Reaction to Hypobaric–Hyperoxic Civilian Flight Conditions
Authors: Nikolaus C. Netzer, Heidelinde Jaekel, Roland Popp, Johanna M. Gostner, Michael Decker, Frederik Eisendle, Rachel Turner, Petra Netzer, Carsten Patzelt, Christian Steurer, Marco Cavalli, Florian Forstner, and Stephan Pramsohler on behalf of the Hypoxiflight Study Group This study aimed to investigate whether flight conditions in a hypobaric chamber, simulating altitudes of 2500 m and 4500 m with varying oxygen levels, could induce oxidative stress in healthy individuals. Twelve vaccinated participants underwent a 3-hour simulation with oxygen levels adjusted between 35% and 100%. Their arterial blood pressure and oxygen saturation were monitored, and blood samples were analyzed for oxidative stress markers at different stages of the experiment.
24 - The Intricate Balance between Life and Death: ROS, Cathepsins, and Their Interplay in Cell Death and Autophagy
Authors: Maya V. Voronina, Anastasia S. Frolova, Ekaterina P. Kolesova, Nikita A. Kuldyushev, Alessandro Parodi, and Andrey A. Zamyatnin Cell survival depends on a balance between the accumulation of damage and repair mechanisms. Oxidants, now recognized as physiological molecules, can damage vital cell components and lead to cell death. Cells counteract this with processes such as autophagy, which recycles damaged parts with the help of lysosomes and enzymes such as cathepsins. These elements help determine whether a cell undergoes apoptosis or autophagy. This review examines the role of ROS and cathepsins in cell death and autophagy, emphasizing their interrelated dynamics.
25 - Progress in the Use of Hydrogels for Antioxidant Delivery in Skin Wounds
Authors: Lidia Maeso, Pablo Edmundo Antezana, Ailen Gala Hvozda Arana, Pablo Andrés Evelson, Gorka Orive, and Martín Federico Desimone Skin is important for protection and healing. Chronic wounds are a worldwide problem caused by oxidative stress that damages cells and delays healing. Proper care and antioxidants can help manage chronic wounds. Natural polymers with antioxidants can create regenerative environments for skin wound healing.
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03 - Further perspectives on measuring pulmonary oxygen uptake kinetics
Authors: Harry B. Rossiter, David C. Poole This text acknowledges and corrects a previous mistake in a scholarly work, clarify the correct references, and engage in a professional discussion about the specifics of breath-by-breath gas exchange measurement algorithms. The authors thank Drs. Francescato and Cettolo for their input, correct the misattribution of an algorithm to Grønlund (1984) instead of the intended IND algorithm, and clarify the context of their references. Additionally, they discuss the technical details of the algorithms and seek agreement on a specific point related to the occurrence of expiration between consecutive inspirations.
04 - Role of Oxygen and Its Radicals in Peripheral Nerve Regeneration: From Hypoxia to Physoxia to Hyperoxia
Authors: Dominik André-Lévigne, Rodrigue Pignel, Sylvain Boet, Vincent Jaquet, Daniel F. Kalbermatten, & Srinivas Madduri This study intends to review and discuss the various roles of oxygen in peripheral nerve regeneration, with a particular focus on the potential therapeutic benefits of hyperbaric oxygen therapy. It highlights the influence of different oxygenation states on nerve repair and regeneration, summarizes current knowledge and data on the effectiveness of hyperbaric oxygen therapy for treating nerve injuries, and suggests future research directions in this area.
14 - Baroreflex dynamics during the rest to exercise transient in acute normobaric hypoxia in humans.
Authors: Anna Taboni, Nazzareno Fagoni, Timothée Fontolliet, Giovanni Vinetti, Guido Ferretti This study investigated the physiological responses during a transition from rest to exercise under hypoxic (H) and normoxic (N) conditions. Specifically, the study aimed to test two hypotheses: (i) that the initial decrease in baroreflex sensitivity (BRS) would be slower in hypoxia compared to normoxia, and (ii) that the fast heart rate (HR) and cardiac output (CO) responses would have smaller amplitudes in hypoxia due to lower vagal activity. The text details the study's methods, results, and conclusions, highlighting the differences in physiological responses between the two conditions.
15 - Depth of SCUBA Diving Affects Cardiac Autonomic Nervous System
Authors: Marina Vulic, Branislav Milovanovic, Ante Obad, Duška Glavaš, Igor Glavicic, Damir Zubac, Maja Valic, & Zoran Valic This study investigated the effects of SCUBA diving at different depths (10 m and 20 m) on heart rate variability (HRV) parameters in healthy individuals to determine if cardiac sympathetic activity adapts proportionally to diving depth and if HRV parameters can track changes in cardiac autonomic nervous system (ANS) function during and after diving. The results indicate that SCUBA diving affects the cardiac ANS, with specific HRV parameters showing significant changes during dives and returning to baseline after ascent. The authors suggest that these HRV markers could be used to monitor cardiovascular risks and potential benefits associated with underwater activities.
16 - Chain of events analysis in diving accidents treated by the Royal Netherlands Navy1966–2023
Authors: Benjamin L Turner, Pieter-Jan AM van Ooij, Thijs T Wingelaar, Rob A van Hulst, Edwin L Endert, Paul Clarijs, Rigo Hoencamp This document discusses a study that applied a 'chain of events analysis' (CEA) framework to understand the causes of diving injuries treated by the Diving Medical Centre of the Royal Netherlands Navy to identify the factors leading to these injuries, including predisposing factors, triggers, disabling agents, and disabling conditions, and to evaluate the effectiveness of the CEA framework in analyzing diving injuries.
17 - Decompression illness: a comprehensive overview
Author: Simon J Mitchell This document provides a comprehensive overview of decompression illness, specifically focusing on the pathophysiology, manifestations, prevention, and treatment of decompression sickness (DCS) and arterial gas embolism (AGE). It aims to educate readers about the causes, mechanisms, and potential health impacts of these conditions, as well as to inform them about how to prevent and manage these diving-related disorders.
18 - Prediction of central nervous system oxygen toxicity symptoms using electrodermal activity and machine learning
Authors: Md-Billal Hossain, Kia Golzari, Youngsun Kong, Bruce J. Derrick, Richard E. Moon, Michael J. Natoli, M. Claire Ellis, Christopher Winstead- Derlega, Sara I. Gonzalez, Christopher M. Allen, Mathew S. Makowski, Brian M. Keuski, John J. Freiberger, Hugo F. Posada-Quintero, Ki H. Chon This study aimed to predict central nervous system oxygen toxicity (CNS-OT) in SCUBA divers by analyzing electrodermal activity (EDA) using machine learning techniques. It focused on the dynamics of EDA while subjects are exposed to elevated oxygen partial pressures in a hyperbaric environment. The goal was to develop a predictive model to identify the onset of CNS-OT symptoms early enough to allow for countermeasures, thereby improving diver safety.
19 - Evolutionary genetics of pulmonary anatomical adaptations in deep-diving Cetaceans
Authors: Boxiong Guo, Yixuan Sun, Yuehua Wang, Ya Zhang, Yu Zheng, Shixia Xu, Guang Yang, & Wenhua Ren This study investigates the evolutionary adaptations in the respiratory systems of cetaceans and other marine mammals. It focuses on the genetic basis of these adaptations, particularly in relation to pulmonary fibrosis and diving behavior. It highlights the identification of specific genes that have undergone accelerated evolution and positive selection and how these genetic changes contribute to lung morphology that reduces the risk of decompression sickness (DCS) during diving. The research also aims to provide insights relevant to understanding human diving physiology.
20 - Physiology of deep closed circuit rebreather mixed gas diving: vascular gas emboli and biological changes during a week-long liveaboard safari
Authors: Costantino Balestra, Clément Lévêque, Simona Mrakic-Sposta, Alessandra Vezzoli, Pierre Wauthy, Peter Germonpré, Frauke Tillmans, François Guerrero, & Pierre Lafère. This study discusses the relationship between diving decompression and inflammatory processes. It aims to test the hypothesis that inflammatory processes can generate micronuclei, which may increase the risks associated with diving. It outlines the methodology, including using echocardiography to count venous gas emboli (VGE) and collecting saliva and urine samples to measure various markers of inflammation. The results indicate a correlation between inflammation and the presence of VGE, suggesting that inflammation may play a role in the formation of micronuclei during diving.
26 - Evaluation of North Sea saturation procedures through divers monitoring
Authors: Jean-Pierre Imbert, Axel Barbaud, Sian Stevens, Craig Miller, Hilary Peace, Helene Rossin, Alain Letourneur, Phil Bryson, Bo Damsgaard, Costantino Balestra This study on saturation diving stressors and the effectiveness of different saturation procedures was conducted in the North Sea Danish sector and aimed to document the level of diving stress and compare the Boskalis and NORSOK procedures. The results indicated minimal stress and no significant differences between the two procedures at depths of 40-50 msw. The authors suggest further research for deeper dives where more significant stress is anticipated.
27 - Volatile Organic Compounds in Cellular Headspace after Hyperbaric Oxygen Exposure: An In Vitro Pilot Study
Authors: Feiko J. M. de Jong, Thijs A. Lilien, Dominic W. Fenn, Thijs T. Wingelaar , Pieter-Jan A. M. van Ooij, Anke H. Maitland-van der Zee, Markus W. Hollmann, Rob A. van Hulst, & Paul Brinkman This paper describes a pilot study to identify volatile organic compounds (VOCs) associated with pulmonary oxygen toxicity (POT) using an in vitro model of alveolar basal epithelial cells exposed to hyperbaric and hyperoxic conditions. It also evaluates the feasibility of using this in vitro model for POT biomarker research and details the experimental protocol, the analysis of VOCs using gas chromatography-mass spectrometry, and the findings, which include significant variations in certain VOCs and increased cellular stress markers in the intervention group.
28 - Apnoea as a novel method to improve exercise performance: A current state of the literature.
Authors: Janne Bouten, Louise Declercq, Jan Boone, Franck Brocherie, Jan G. Bourgois This document evaluates the potential of apnoea as a training method to enhance aerobic performance and discusses the effectiveness of different apnoea protocols. It concludes that while apnoea-induced spleen contraction can improve oxygen uptake kinetics, it does not immediately enhance aerobic performance. Additionally, only long and intense apnoea protocols in experienced individuals show significant increases in erythropoietin and reticulocytes. The authors suggest that variations of apnoea training may have potential for improving exercise performance.
29 - Post-exercise hot or cold water immersion does not alter perception of effort or neuroendocrine responses during subsequent moderate-intensity exercise
Authors: Campbell Menzies, Neil D. Clarke, Christopher J. A. Pugh, Charles J. Steward, C. Douglas Thake, Tom Cullen This document presents the findings of a scientific study that investigated the effects of post-exercise hot water immersion (HWI) and cold water immersion (CWI) on recovery and subsequent performance in endurance- trained runners. It determines whether these recovery strategies influence physiological and psychological responses, as well as performance in a second training session performed later the same day. The results suggest that while HWI and CWI affect certain physiological markers, they do not negatively impact perceived effort, recovery, or performance in subsequent moderate- intensity training sessions.