Improving cognitive function following exercise-induced dehydration: Role of sports drink supplementation

Objective: While brief bouts of exercise improve cognitive function, more prolonged exercise can suppress attention and executive function. Dehydration and heat exposure are known contributors to these deficits, though the role of blood sugar changes during exercise in cognitive dysfunction is less understood at this time. The current study sought to clarify the independent contribution of blood glucose levels to cognitive function following demanding exercise. Method: Healthy adult males (N= 10, age= 21.9 +/- 1.97 years) presented for two counterbalanced experimental trials in a 100 degrees F heated chamber. Each experimental trial consisted of BASELINE glucose and cognitive function assessments, as measured by the Logical Relations (LR) and Running Memory Continuous Performance Task (RMCPT) subtests of the Automated Neuropsychological Assessment Metrics- 4th Edition (ANAM4). Participants then completed 120 minutes of exercise on a cycle ergometer, with glucose and cognitive function measured POST-EXERCISE. Next, participants rehydrated with a zero-sugar or full-sugar sports beverage, with measures of glucose and cognitive function repeated immediately POST-REHYDRATION. Finally, after a 15-minute recovery period during which the participants rested while not permitted to drink, they completed experimental measures an additional time, at POST-RECOVERY. Results: Physiological response to the experimental trials was similar across conditions. Participants demonstrated significantly reduced blood glucose levels (F(1,9)=16.93, p<0.01) and lost an average of 2.57% of their body weight following exercise. Contrary to hypotheses, repeated measures ANOVA showed performance on LR did not change from BASELINE to POST-EXERCISE and actually declined from POST-EXERCISE to POST-REHYDRATION (F(1,9)=9.44, p=0.01). Performance on RMCPT improved from BASELINE to POST-EXERCISE (F(19)=5.43, p