Effects of Aerobic Exercise on Frontal EEG Asymmetry, Coherence and Mood: A Pilot Study

Abstract

Introduction: Electroencephalographically-measured frontal alpha asymmetry is shown to reflect changes in mood. Negative mood changes are purported to limit exercise capacity in some groups, thereby contributing to the current epidemic of overweight, obesity and related diseases. Aim: This study tests the hypothesis that the mood changes associated with aerobic exercise are correlated with changes in frontal EEG asymmetry. Materials and Methods: Healthy young adult African-American (AA) men (n=8) and women (n=8) were subjected to quantitative EEG brain mapping of delta, theta, alpha and beta bandwidths after a period of rest or a period of aerobic exercise at a fixed energy expenditure. Brain mapping was performed within 30 min after rest or exercise, immediately before completing a questionnaire which included a total mood disturbance score (tMDS) and specific mood subcategory scores consisting of vigor, fatigue, anger, confusion tension, depression. Prefrontal and inferior frontal asymmetry were evaluated. Significance of differences between rest and exercise prefrontal and inferior frontal asymmetry was evaluated by one-way ANOVA. Results: Exercise-related decrements in asymmetry were significant for prefrontal delta (p≤0.05) and marginally significant for prefrontal alpha and theta (p=0.07) in the male subjects. There were significant decrements in tension and tMDS for the males and females and a decrement in depression score for the females between the post-control rest and the post-exercise conditions. Significant negative correlation between the tMDS and prefrontal beta asymmetry was found, across post-rest and post-exercise (r= -0.38, p≤0.05, 30 df). There were also significant correlations between confusion and prefrontal beta asymmetry during rest (r= 0.48, p≤0.05, 14 df), between vigor and inferior frontal beta asymmetry, between vigor and both inferior frontal theta asymmetry and inferior frontal delta asymmetry during exercise (r= 0.46, -0.54, p≤0.05, 14 df), and between vigor, confusion, tension and inferior frontal delta asymmetry post-exercise (r= -0.49, -0.45, -0.49, p≤0.05, 14 df). Conclusion: The high prefrontal beta asymmetry associated with depressed mood in AA males and females, the lessening of prefrontal delta, theta and alpha asymmetry in the males and the lower depression scores after aerobic exercise in the females seem to support the hypothesis that decreased asymmetry with increased activation of the right prefrontal and frontal cortices may accompany the mood changes associated with aerobic exercise.

Keywords

• african americans
• brain mapping
• mood changes