Executive function following acute exercise at different intensities

A single bout of acute exercise has a positive influence on basic information processing tasks such as simple reaction time (Tomporowski and Ellis, 1986, Psychological Bulletin, 99, 338–346). Although similar cognitive improvements have been observed in more complex, executive function tasks, including visual search and short-term memory tasks, the research findings are less consistent (Chang, Labban, Gapin, and Etnier, 2012, Brain Research, 1453, 87–101). Previous studies have employed various exercise modes, duration and intensities, as well as differences in the nature and timing of the psychological task, which may explain the inconsistent findings (Chang et al., 2012). Therefore, the improvement in cognitive function following acute exercise needs further investigation. Identification of an optimal exercise intensity could be used to improve executive functioning in sport, occupational (e.g. military) or academic settings. The aim of the present study was to determine whether an acute bout of treadmill running at different intensities affects performance on an executive functioning task. With institutional ethics approval, 21 healthy adult males (mean age 20.8 years, s = 1.6; body mass 79.9 kg, s = 10.4) completed a maximal incremental graded exercise test to establish maximal oxygen uptake (V_ O2max). Thereafter, participants performed an executive functioning task immediately prior to and following either 30 min of rest or treadmill running at three different exercise intensities determined by V_ O2max; light (30% V_ O2max), moderate (50% V_ O2max) and hard (70% V_ O2max) workloads. The modified flanker test was used to assess executive function (Eriksen and Eriksen, 1974, Perceptual Psychophysiology, 16, 143–149). Repeated measures analysis of covariance (ANCOVA) for time was employed to assess the main effect of exercise intensity on reaction times (RT; ms) and error rate (%). RT significantly improved following exercise (P < 0.01). Pairwise comparisons indicated that RT following hard exercise was significantly faster (m = 471.07 ms, s = 4.53) than either no exercise (m = 494.05, s = 4.62) or light exercise (m = 492.04 ms, s = 4.59) (P < 0.01, 95% Cl 6.786–41.186; P < 0.01, 95% Cl 3.820–38.140, respectively). Accuracy of response was not significantly affected by exercise (P > 0.05). The present results suggest that treadmill running at 70% of V_ O2max signifycantly improves executive functioning and could be a useful tool when employed to improve the performance of complex cognitive tasks in sport, occupational or academic settings.