Oxidative stress assessment in breath-hold diving
Breath-hold diving results in significant changes in blood gases’ levels. Challenging variations in oxygen partial pressures may induce reactive oxygen species (ROS) production that exacerbate oxidative stress and, consequently, affect endothelial function. The aim of this study was to investigate the effects of breath-hold diving on oxidative stress damage, assessing ROS production. Nitric oxide metabolites, inducible nitric oxide synthase (iNOS), aminothiols, and renal function were evaluated too as markers of redox status and renal damage.
ROS production was assessed with electron paramagnetic resonance. Oxidative status values were measured at pre- and post-40 m dive in a deep swimming pool (Y-40) from six divers (mean age 46.6 ± 9.3 years; height 176 ± 4 cm; BMI 25 ± 2.9 kg/m2).
Significant (p < 0.05) increases at post-dive of ROS production rate (0.158 ± 0.003 vs 0.195 ± 0.006 μmol min−1), lipid peroxidation (8-isoprostane: 375.67 ± 195.62 vs 420.49 ± 232.31 pg mg−1 creatinine), nitrate (27.91 ± 19.71 vs 30.80 ± 20.44 μM), iNOS (31.30 ± 4.52 vs 35.68 ± 6.72 IU mL−1) and neopterin concentration (96.20 ± 40.41 vs 118.76 ± 27.84 μmol mol−1 creatinine) were recorded. Conversely, the antioxidant capacity significantly decreased (3.423 ± 0.089 vs 3.015 ± 0.284 mM) after immersion.
Overproduction of ROS and consequent oxidative damage to lipids of membrane and antioxidant capacity decreasing reflect also a hypoxic condition, which in the breath-hold diving typically occurs in the last few meters below the surface. iNOS produces NO in large quantities under the examined extreme conditions. Neopterin and creatinine concentration level increased, suggesting an “impairment of renal function” as a likely physiological response to PaO2 variations during dive activity.
KeywordsReactive oxygen species Nitric oxide Electron paramagnetic resonance Breath holding
Electron paramagnetic resonance
High-performance liquid chromatography
Inducible nitric oxide synthase
Reactive oxygen species
Total antioxidant capacity
The authors would like to thank the deepest swimming pool Y-40 THE DEEP JOY, (Montegrotto Terme—Padua Italy) and also thank the divers (M. Mardollo, P. Parzanese, A. Calesella, M. Lorenzi, T. D’Onofrio, R. Minelli, E. Pozzo, G. Calitri) for participating in this study.
All experiments were performed at the deepest swimming pool Y-40 THE DEEP JOY, (Montegrotto Terme—Padua Italy), at the university of Padova (Padova, Italy) and National Research Council (Milano, Italy). SMS contributed to the study design, data analysis, interpretation and drafting of the manuscript. AV, CDN and MM contributed to the data analysis and interpretation, critical review of the manuscript; AR, MP, SM and PC contributed to the data collection and critical review of the manuscript; GB contributed to the study design, data collection and data interpretation, and critical review of the manuscript. GB confirms the study objectives and procedures are honestly disclosed. All the authors approved the final version of the manuscript.
Compliance with ethical standards
Conflict of interest
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