Exercise-heat stress with and without water replacement alters brain structures and impairs visuomotor performance

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Matthew T.,Sawka,Michael N.,Mizelle,J. C.,Wheaton,Lewis A. Wittbrodt (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Effects of exercise-heat stress with and without water replacement on brain structure and visuomotor performance were examined. Thirteen healthy adults (23.6 ± 4.2 years) completed counterbalanced 150 min trials of exercise-heat stress (45°C, 15% RH) with water replacement (EHS) or without (~3% body mass loss; EHS-DEH) compared to seated rest (CON). Anatomical scans and fMRI Blood-Oxygen-Level-Dependent responses during a visuomotor pacing task were evaluated. Accuracy decreased (P < 0.05) despite water replacement during EHS (−8.2 ± 6.8% vs. CON) but further degraded with EHS-DEH (−8.3 ± 6.4% vs. EHS and −16.5 ± 10.2% vs. CON). Relative to CON, EHS elicited opposing volumetric changes (P < 0.05) in brain ventricles (−5.3 ± 1.7%) and periventricular structures (cerebellum: 1.5 ± 0.8%) compared to EHS-DEH (ventricles: 6.8 ± 3.4, cerebellum: −0.7 ± 0.7; thalamus: −2.7 ± 1.3%). Changes in plasma osmolality (EHS: −3.0 ± 2.1; EHS-DEH: 9.3 ± 2.1 mOsm/kg) were related (P < 0.05) to thalamus (r = −0.45) and cerebellum volume (r = −0.61) which, in turn, were related (P < 0.05) to lateral (r = −0.41) and fourth ventricle volume (r = −0.67) changes, respectively; but, there were no associations (P > 0.50) between structural changes and visuomotor accuracy. EHS-DEH increased neural activation (P < 0.05) within motor and visual areas versus EHS and CON. Brain structural changes are related to bidirectional plasma osmolality perturbations resulting from exercise-heat stress (with and without water replacement), but do not explain visuomotor impairments. Negative impacts of exercise-heat stress on visuomotor tasks are further exacerbated by dehydration.

Additional Information

Publication

Other

Language: English

Date: 2018

Keywords

Brain anatomy; cognition; dehydration; heat stress; motor function

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