Body-heart-brain Interaction On Exercise

Abstract

Recent work suggests that inhibitory control influences affective regulation and is an important neurobiological mechanism that contributes to physical activity behavior. However, the effects of exercise intensity in this complex interaction body-heart-brain remain unclear. PURPOSE: Investigate the effects of exercise intensity on inhibitory control, affect, autonomic function and prefrontal cortex (PFC) oxygenation. METHODS: 37 sedentary young adults were randomly assigned to two experimental conditions (control or exercise). For the exercise condition, a maximum incremental test was performed on a cycle ergometer with continuous measurements of PFC oxygenation, heart rate variability (HRV), inhibitory control (Stroop test), associative and dissociative thoughts (ADT) and affect scale every 2 minutes at each of 8 intensity increments. For the control condition, the same assessments were carried out, but participants sat on a cycle ergometer without active pedaling. We evaluated the effects with a two-way repeated measures ANOVA with Bonferroni adjustments to compare the effects and interactions of condition and intensity. Then, Pearson’s correlations to evaluate the relationship between affect and inhibitory control, ADT, HRV and PFC oxygenation. RESULTS: Intensities above the ventilatory threshold (VT) induced poorer inhibitory control (F=33.64; p<0.001), more ratings of unpleasantness (F=200.60; p<0.001), increased HRV activity (F=29.96; p<0.001) and increased oxygenation of the PFC (F=55.97; p<0.001). Pleasure perception was correlated with ADT at almost all intensities from 2-VT to VT+2 (rs>-0.33, ps<0.05). We also found pleasure correlation with HRV lower frequencies analysis (r=-0.34; p<0.05) and ratio between low and high frequency (r=-0.33; p<0.05), in the last stage of intensity, and to PFC deoxy was found at VT+2 intensity (r=-0.37; p<0.05). CONCLUSION: Exercise at high intensities reduces inhibitory control and affect (ratings of pleasantness). Displeasure correlates to increases in thoughts associated to exercise, and at high intensities, displeasure is correlated with PFC deoxygenation and sympathetic activity. These findings strengthen the existence of an integrative body-heart-brain system and suggests a role of the exercise intensity in this interaction.