title: Extreme Mountain Ultra-Marathon Leads to Acute but Transient Increase in Cerebral Water Diffusivity and Plasma Biomarkers Levels Changes.
abstract: Background:Pioneer studies demonstrate the impact of extreme sport load on the human brain, leading to threatening conditions for athlete's health such as cerebral edema. The investigation of brain water diffusivity, allowing the measurement of the intercellular water and the assessment of cerebral edema, can give a great contribution to the investigation of the effects of extreme sports on the brain. We therefore assessed the effect of supra-physiological effort (extreme distance and elevation changes) in mountain ultra-marathons (MUMs) athletes combining for the first time brain magnetic resonance imaging (MRI) and blood parameters.Methods:This longitudinal study included 19 volunteers (44.2 ± 9.5 years) finishing a MUM (330 km, elevation + 24000 m). Quantitative measurements of brain diffusion-weighted images (DWI) were performed at 3 time-points: Before the race, upon arrival and after 48 h. Multiple blood biomarkers were simultaneously investigated. Data analyses included brain apparent diffusion coefficient (ADC) and physiological data comparisons between three time-points.Results:The whole brain ADC significantly increased from baseline to arrival (p= 0.005) and then significantly decreased at recovery (p= 0.005) to lower values than at baseline (p= 0.005). While sodium, potassium, calcium, and chloride as well as hematocrit (HCT) changed over time, the serum osmolality remained constant. Significant correlations were found between whole brain ADC changes and osmolality (p= 0.01), cholesterol (p= 0.009), c-reactive protein (p= 0.04), sodium (p= 0.01), and chloride (p= 0.002) plasma level variations.Conclusions:These results suggest the relative increase of the inter-cellular volume upon arrival, and subsequently its reduction to lower values than at baseline, indicating that even after 48 h the brain has not fully recovered to its equilibrium state. Even though serum electrolytes may only indirectly indicate modifications at the brain level due to the blood brain barrier, the results concerning osmolality suggest that body water might directly influence the change in cerebral ADC. These findings establish therefore a direct link between general brain inter-cellular water content and physiological biomarkers modifications produced by extreme sport.
authors.affiliation: Department of Psychiatry, University Hospital of Basel Basel, Switzerland.
authors.forename: Davide
authors.initials: D
authors.lastname: Zanchi
authors.affiliation: CREATIS, Centre National de la Recherche Scientifique UMR 5220, INSERM U1206, Université de Lyon, INSA Lyon, Université Jean Monnet Saint-EtienneSaint Etienne, France; Radiology Department, CHU de Saint EtienneSaint Etienne, France.
authors.forename: Magalie
authors.initials: M
authors.lastname: Viallon
authors.affiliation: Department of Clinical Chemistry, University of Liège Liège, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Le Goff
authors.affiliation: Institute of Sports Sciences, University of Lausanne Lausanne, Switzerland.
authors.forename: Grégoire P
authors.initials: GP
authors.lastname: Millet
authors.affiliation: Department of Neurology and Stroke Unit, Mountain Medicine and Neurology Center Valle d'Aosta Regional Hospital Aosta, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Giardini
authors.affiliation: CREATIS, Centre National de la Recherche Scientifique UMR 5220, INSERM U1206, Université de Lyon, INSA Lyon, Université Jean Monnet Saint-EtienneSaint Etienne, France; Radiology Department, CHU de Saint EtienneSaint Etienne, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Croisille
authors.affiliation: Affidea Centre de Diagnostic Radiologique de Carouge CDRCGeneva, Switzerland; Faculty of Medicine, University of GenevaGeneva, Switzerland; Department of Surgical Sciences, Radiology, Uppsala UniversityUppsala, Sweden; Department of Neuroradiology, University Hospital FreiburgGermany.
authors.forename: Sven
authors.initials: S
authors.lastname: Haller
keywords: MRI; apparent diffusion coefficient; brain; extreme sport; ultra-marathon