Saturday Morning Poster Presentations: Posters displayed from 7:30–11:00 a.m.: One-hour author presentation times are staggered from 8:00–9:00 a.m., 9:00–10:00 a.m., and 10:00–11:00 a.m.: G-19 Free Communication/Poster – Physical Activity, Cognition and Cognitive Function: SATURDAY, JUNE 3, 2006 8:00 AM – 11:00 AM ROOM: Hall B
Recently, some investigators have suggested that acute exercise affects cognitive function which is reflected in P300 of event-related brain potentials. However, the often contradictory findings of experimental research have led several authors to identify four methodological factors to control in such studies: (i) the physical fitness of subjects, (ii) the intensity and duration of physical exercise, (iii) the nature of the psychological task, and (iv) the time at which the psychological task was administered to the subjects. In regard to the fourth factor, these studies are mainly divided into two types through differences in the timing of P300 measurements. One type conducts measurements immediately after exercise, whereas the other type carries out measurements after the body temperature and/or heart rate (HR) has returned to the baseline level. The present study focused on the fourth factor.
PURPOSE: The aim of this study was to investigate the effects of acute exercise on cognitive function by differential timing of P300 measurements.
METHODS: Fourteen subjects (24.21 ± 1.32 yrs) performed a go/no-go reaction time task, which consisted of a warning stimulus (S1) followed 2 sec later by an imperative stimulus (S2), without cycling before (pre), immediately after (post1), and after their esophageal temperature (Tes) and HR had returned to pre-exercise values (post2). Exercise intensity was set at 65%HRmax, with a duration of 30 min.
RESULTS: Tes rose from 36.74 ± 0.03°C to 37.11 ± 0.07°C after exercise. Time to Tes recovery (between the end of exercise and post2) was 27.37 ± 2.10 min. P300 latency showed no change. Although P300 amplitude at post1 was significantly larger than that of the pre, P300 amplitude at post2 showed no change. The pattern of changes in early contingent negative variation (CNV) amplitude was similar to P300.
CONCLUSIONS: P300 latency was not influenced by increases in body temperature in this study. Increase in P300 amplitude observed at post1 indicated that acute exercise facilitated cognitive function. Then, it was considered that the change in P300 immediately after exercise was influenced by the exercise-induced arousal level, because the increase in early CNV amplitude was observed only at post1. But, the psychological effects of exercise on cognitive function did not last long in the exercise condition used in this study.