Influences Of Acute Physical Activity And Sedentary Behavior On Brain Hemodynamic Responses And Inhibitory Control

Brett Baker1 and Darla Castelli2Huston-Tillotson University, Austin, TX1University of Texas at Austin, Austin, TX2 PURPOSE: To determine how 30-minute bouts of sedentary behavior (SB) and physical activity (PA) influenced brain oxygenated hemoglobin (HbO2) and inhibitory control (IC). We hypothesized that SB would significantly diminish HbO2 and IC while PA would significantly enhance HbO2 and IC. METHODS: Forty-one healthy young adults (mean age = 21.3 ± 2.6 years) participated in this study and were randomized into either 30-min of SB or 30-min of PA. The SB group sat in a recliner and watched a non-stimulating history documentary while the PA group walked a predetermined route for 30 minutes. HbO2 and IC were assessed simultaneously pre/post by using functional near-infrared spectroscopy (fNIRS) and the Flanker Task, respectively. Our HbO2 montage measured the prefrontal cortex and included 8 sources and 7 detectors for a total of 20 channels. HbO2 and IC data were analyzed by paired sample and independent samples t-tests in SPSS. RESULTS: Thirty minutes of SB did not significantly change IC from pretest measures. The PA condition produced significantly faster reaction times on both the Flanker Congruent (445.6 ± 46.9 ms vs. 427.9 ± 34.5 ms, p = 0.020) and Flanker Incongruent (487.1 ± 49.4 ms vs. 464.8 ± 35.9 ms, p = 0.004) tasks. The SB condition was associated with significant increases in prefrontal cortex HbO2 while 30 minutes of PA was associated with significant decreases in prefrontal cortex HbO2 (p < 0.05). The significant changes in HbO2 concentrations were in the dorsolateral prefrontal cortex. CONCLUSIONS: Contrary to our hypotheses, SB led to an increase in HbO2 while PA led to a reduction in HbO2. However, the benefits of PA and the associated improvements in IC with a simultaneous attenuation of HbO2, reflects greater efficiency of neural processing not seen in the SB group. FACSM Sponsor: Edward Coyle, PhD