Cardiorespiratory Fitness Influences Cognitive Variability Response To High Intensity Cycling

BACKGROUND: Although considerable evidence suggests cardiorespiratory fitness (CRF) to play key role in supporting cognitive health and function, the extent of this relationship is not yet fully characterized. One current gap in the literature is the use of measures of central tendency which averages outcomes over numerous trials. This approach over looks intra-individual variability (IIV) that is suggested to index neural efficiency and may serve as a more sensitive marker of cognitive health. Furthermore, while there is evidence supporting greater CRF may enhance the exercise-induced cognitive enhancements and that IIV may represent a specific adaptation to exercise, no works have yet explored how CRF may influence changes in IIV following an acute bout of exercise. PURPOSE: Accordingly, this study sought to examine how CRF may influence exercise induced changes in IIV. METHODS: 19 participants (26.1 ± 5.0 yrs) completed a randomized cross-over trial. All participants completed maximal exercise testing on a stationary ergometer with VO2 peak as a measure of CRF. Participants were then randomized into the exercise condition (30-minutes of cycling at VTh + 10%) or sedentary control for their subsequent visits. Before and after the exercise and sedentary control conditions, participants completed the Eriksen flanker task while wearing an electroencephalogram (EEG) cap to record the P3, a neuroelectric index of attentional resource allocation. Associations between CRF and changes in cognitive outcomes were assessed through linear mixed models with CONDITION, VO2, CONDITION x VO2 as fixed effects and participant intercept as a random effect. RESULTS: VO2 was associated with reductions in congruent reaction time variability (B = -0.88, p = 0.023) and P3 latency variability (congruent: B = -1.01, p = 0.017; incongruent: B = -0.70, p = 0.023) following the exercise but no associations with changes in either congruent reaction time variability (B = -0.58, p = 0.161) or P3 latency variability (congruent: B = -0.02, p = 0.956; incongruent: B = 0.06, p = 0.816) following the sedentary condition. CONCLUSION: These findings suggest that individuals with greater CRF exhibit greater neural efficiency and consistency which may highlight the unique properties of IIV in understanding the cognitive response to exercise. Supported by: University of Illinois Campus Research Board