REGIONAL BRAIN ACTIVATION AS A BIOLOGICAL MARKER OF AFFECTIVE RESPONSIVITY TO MAXIMAL EXERCISE

Abstract

771 Previous research has demonstrated that resting regional brain activation is predictive of affective responses following submaximal (≥70% VO2max) aerobic exercise. In an effort to examine the upper limits of this predictive range, regional brain activation (via EEG: F3, F4, P3, P4; linked-ears reference) was assessed before a graded maximal treadmill test in 30 subjects (M±SEM: 17♂ 24.4 ± 1.0 yrs, VO2max=51.54 ± 1.70 ml·kg−1·min−1; 13♀ 23.2 ± 0.8 yrs; VO2max=47.30 ± 1.10 ml·kg−1·min−1). Affect was assessed before and 0, 10, and 20 min post-test via Thayer's Activation-Deactivation Adjective Check List, which yields measures of Energetic Arousal (Energy, Tiredness) and Tense Arousal (Tension, Calmness). Hierarchical regression analyses revealed that, after partialling out VO2max and pre-exercise affect, resting frontal asymmetry accounted for 22% unique variance in Tiredness (B=.47, P=0.009) at 10-min and 17% (B=.41, P=0.034) at 20-min, and 14.5% unique variance in Calmness (B=.39, P=0.049) at 10-min post-test. In the most Left-Activated (LA) individuals (n=10; M±SEM asymmetry= 0.052 ± 0.01), frontal asymmetry predicted unique variance in both Tiredness (41.5%, B=.66, P=0.047) and Calmness (42.6%, B=.74, P=0.042) at 10-min post-test. In the most Right-Activated (RA) individuals (n=10; M±SEM asymmetry=−0.077 ± 0.01), frontal asymmetry predicted unique variance only in Calmness (56.4%, B=.84, P=0.026) at 20-min post-lest. Parietal EEG did not account for unique variance in any measure of affect. Thus, relatively greater left frontal activation predicted post-exercise increases in low activation states (Calmness, Tiredness) in LA individuals whereas it predicted a low activated, pleasant state (Calmness) in RA individuals. These findings extend previous exercise-EEG research, further supporting the notion that affective responses to exercise are mediated, in part, by differential levels of activation in the anterior portions of the brain. These responses are varied, complex and appear to be sensitive to dose characteristics.