3150m 상당의 평압·저산소 환경에서 Ergometer 운동이 뇌파에 미치는 영향

Purpose: The cerebral blood flow velocity (CBFV) response to acute hypoxia has been known to increase. But, how CBFV might respond to exercise in hypoxic condition and how it is associated with EEG remains unclear. The purpose of this study is to determine the effect of hypoxia on electroencephalographic activity during and after cycle ergometer exercise. Method: In a randomized, double-blind, crossover study, twelve healthy volunteers (21.4±0.7yrs) were asked to perform the bicycle ergometer exercise twice in hypocx icondition and control (sea level) condition with a week interval, respectively. Exercise intensity was set initially at 50W and increased by 25W every 2 minutes until 125W, then maintained at 125W for 14 minutes. Acute normobaric hypoxic condition corresponding to the altitudes of 3150m was maintained using low oxygen gas mixture for the whole procedure of 60 minutes. EEG was measured prior to the onset of exercise, immediately after exercise and 20 minutes recovery. EEG signal was recorded from 6 scalp sites (frontal, temporal nad occipital lobe of the international 10-20 system) leading to analysis of theta (4-7Hz), alpha (8-13Hz), ebta (13-30Hz), and gamma(30-50Hz) relative activities. All data were analyzed using two-way ANOVA with repeated measures. Results: Alpha wave activity of frontal lobe in hypoxia group was sigifnicantly lower than in control group immediately after exercise (0.24±0.13 vs. 0.41±0.15 ㎶, p<.05). Beta wave activity of occipital lobe in hypoxia group was significantly higher than in control group immediateyl after exercise (0.28±0.07 vs. 0.20±0.07 ㎶ , p<.05). Gamma wave activity of frontal lobe in hypoxia group was ignificantly higher than in control group immediately after exercise (0.25±0.12 vs. 0.12±0.08 ㎶, p<.05). Theta wave activity of left frontal lobe in hypoxia group was significantly lower than in control group at 20 minutes recovery (0.08±0.05 vs. 0.15±0.05 ㎶, p<.05). Conclusion: These results suggest that acute exposure to mild hypoxic condition may amplify the change of EEG activities which has been commonly observed during exercise.