급성 저산소 노출에서의 자전거 에르고미터 운동이 중대뇌동맥 혈류속도와 뇌신경활성에 미치는 영향 = Effects of Bicycle Ergometer Exercise on Cerebral Blood Flow Velocity and Electroencephalogram Response in Normoxia and Hypoxia

다국어 초록 (Multilingual Abstract)

Background: The cerebral blood flow velocity (CBFV) has been known to increase in response to acute hypoxia. However, how CBFV might respond to exercise in hypoxic conditions and be associated with electroencephalogram (EEG) remains unclear. The purpose of this study was to evaluate the effect of exercise in hypoxic conditions corresponding to altitudes of 4,000 m on CBFV and EEG.
Methods: In a randomized, double-blind, balanced crossover study, ten healthy volunteers (19.8±0.4 years) were asked to perform the incremental bicycle ergometer exercise twice in hypoxic and control (sea level) conditions with a 1-week interval, respectively. Exercise intensity was set initially at 50 W and increased by 25 W every 2 minutes to 125 W. Acute normobaric hypoxic condition was maintained for 45 minutes using low oxygen gas mixture. CBFV in the middle cerebral artery (MCA) and EEG were measured at rest 5 minutes, rest 15 minutes, immediately after exercise, and 15 minutes recovery using transcranial-Doppler sonography and EEG signal was recorded from 6 scalp sites leading to analysis of alpha and beta wave relative activities. All data were analyzed using two-way repeated-measures analysis of variance and Pearson’s correlation.
Results: CBFV in the MCA in the hypoxic condition was significantly higher than that in the control condition at rest 5 minutes (83±9 vs. 69±9 cm/s, P<0.01), rest 15 minutes (87±8 vs. 67±7 cm/s, P<0.001), immediately after exercise (112±9 vs. 97±9 cm/s, P<0.01), and 15 minutes recovery (91±11 vs. 74±7 cm/s, P<0.01). However, no significant correlation was found between the changes of CBFV and EEG wave activities.
Conclusions: These results suggest that the drastic change of CBFV observed during exercise with hypoxia might appear independently with EEG wave activities.

국문 초록 (Abstract)

연구배경: 일회적인 저산소 상황은 대뇌혈류속도를 증가시키는 것으로 알려져 있다. 하지만 대뇌혈류속도가 저산소가 노출된 상황에서 운동 중에 어떤 반응을 초래할지 그리고 이러한 반응이 뇌파와 어떤 관련이 있는지를 관찰한 연구는 미비한 실정이다.
방법: 본 연구에 참여한 10명의 건강한 성인 남성은 저산소 노출과 비처치가 교차되도록 무작위 배정되었다. 에르고미터 운동은 점진적으로 부하를 주었으며 평압·저산소 노출은 저산소 환경 조절장비를 이용하여 45분간 유지되었다.
대뇌혈류속도와 뇌파는 각각 네 번의 시점에서 측정되었다.
측정된 모든 데이터는 이원반복측정 분산분석을 이용하여분석하였으며 아울러 피어슨의 상관관계를 이용하여 상관도를 분석하였다.결과: 저산소집단의 중대뇌동맥 혈류속도는 통제집단에비하여 안정시 5분(83±9 vs. 69±9 cm/s, P<0.01), 안정시 15분(87±8 vs. 67±7 cm/s, P<0.001), 운동 종료 직후(112±9 vs.
97±9 cm/s, P<0.01) 그리고 회복기 15분(91±11 vs. 74±7 cm/s, P<0.01)에 유의하게 높은 것으로 나타났다. 하지만 중대뇌동맥 혈류속도 변화와 뇌파 활성도 변화는 상관관계가나타나지 않았다.
결론: 이 결과는 저산소 환경에서 운동시 관찰된 대뇌혈류속도의 급격한 변화가 뇌파 활동과 독립적으로 나타날 수있음을 시사한다.

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