Oxidative stress and motion sickness in one crew during competitive offshore sailing

Abstract

Competitive Offshore Ocean Sailing is a highly demanding activity in which subjects are exposed to psychophysical stressors for a long time. To better define the physiological adaptations, we investigated the stress response of subjects exposed to 3-days long ocean navigation with disruption of circadian rhythms. 6 male subjects were involved in the study and provided urine and saliva samples before setting sail, during a single day of inshore sailing, during 3-days long ocean navigation, and at the arrival, to measure oxidative stress, cortisol, nitric oxide metabolites (NOx) and metabolic response. Motion Sickness questionnaires were also administered during the navigation. The crew suffered a mean weight loss of 1.58 kg. After the long navigation, a significant increase in ROS production and decrease in total antioxidant capacity and uric acid levels were observed. Lipid peroxidation, NO metabolites, ketones, creatinine, and neopterin levels were also increased. Furthermore, a significant increase in cortisol levels was measured. Finally, we found a correlation between motion sickness questionnaires with the increase of NOx, and no correlation with cortisol levels. Physical and psychological stress response derived from offshore sailing resulted in increased oxidative stress, nitric oxide metabolites, and cortisol levels, unbalanced redox status, transient renal function impairment, and ketosis. A direct correlation between motion sickness symptoms evaluated through questionnaires and NOx levels was also found.

Figure 1

Sketch of the experimental protocol and map showing the navigation route. Data were collected before departure (PRE), during the inshore navigation (Training) during each day of Offshore Ocean Sailing (from 1° to 3° day), and at arrival (POST). GPS data and map were obtained with Spot Gen3, SPOT LCC, Globastar, Inc, Covington, Louisiana, USA. Maps by Google, Inst. Geogr. Nacional. Modified geographic map was edited with Microsoft Office PowerPoint 2007, Microsoft Corporation, Washington, USA, version 16.16.27, https://www.microsoft.com/it-it/microsoft-365/powerpoint and at the top was insert the experimental protocol timeline.

Figure 2

Biomarkers kinetic. Time course of: (A) radical oxygen species (ROS) production rate (μmol·min⁻¹) and (B) total antioxidant capacity (TAC—mM) in saliva assessed by EPR; (C) uric acid (mM); (D) 8-isoprostane (8-iso-PGF2α, pg mg⁻¹ creatinine); (E) nitric oxide metabolites (NOx, μM), (F) creatinine (g L⁻¹), (G) neopterin (μmol mol⁻¹creatinine), concentrations detected in urine. In (H) cortisol levels (ng/mL) measured in saliva. *p < 0.05, **p < 0.01, ***p < 0.001 significantly different. Figure created with: GraphPad Prism, GraphPad Software inc. California, USA, version 9.0.1, https://www.graphpad.com/.

Figure 3

Relationship panel plot of: (A) NOx and GSRS during navigation; (B) GSRS and general discomfort of MSQ at 1st day; at the 2nd day, the panels show the correlation between GSRS and specific items of MSQ. (C) General discomfort and GSRS. (D) Dizziness as illusory sense of motion (eyes open) and GSRS. (E) Stomach awareness and GSRS. A significant linear relationship (p < 0.05–0.001) between parameters was estimated. The correlation coefficient (r), Chi-Square (χ²) and Phi coefficient (ϕ) are reported. Figure created with: GraphPad Prism, GraphPad Software inc. California, USA, version 9.0.1, https://www.graphpad.com/.