학술논문
대학 보디빌딩 선수의 대사적수용기 자극에 따른 심혈관반응 / Resistance exercise training enhances the muscle metaboreflex during post-exercise forearm occlusion.
Document Type
Dissertation/ Thesis
Author
Source
Subject
Language
Korean
Abstract
본 연구는 정상 혈압자 중에서 장기간 저항성 운동을 지속해온 대학 보디빌딩 선수와 규칙적인 운동 경험이 없는 일반대학생에게 상대적으로 동일한 운동강도(MVC 60%)의 rhythmic handgrip exercise(3분)를 수행한 후 ischemia 유발(2분)을 통하여 대사적수용기를 자극함으로써 나타나는 metaboreflex sensitivity와 심혈관반응의 차이를 검토하였다. 그 결과 ischemia시 대학 보디빌딩 선수에게서 낮은 metaboreflex sensitivity 경향이 나타났으며, 심혈관반응에서는 그룹간의 CO의 차이는 없었지만 대학 보디빌딩 선수에게서 높은 TVC 경향이 제시되었다. 따라서 장기간의 저항성 운동을 통한 혈압 감소 기전에는 대사적 수용기가 중요한 역할을 하고 있으며 증가된 TVC에 의한 혈압 감소 메카니즘을 제시할 수 있다.
Previous studies have shown that resistive exercise training such as isometric handgrip exercise or weightlifting decreases arterial blood pressure. However, the mechanisms responsible for reduction in arterial blood pressure have not been investigated. One mechanism that may lower arterial blood pressure is a neural mechanism termed the muscle metaboreflex that is activated when oxygen delivery to active skeletal muscle falls below a critical level. The muscle metaboreflex, a component of exercise pressor reflex, increases the sympathetic activity to heart and vasculature and then increases arterial blood pressure, cardiac output, and ventilation during exercise. Therefore, the purpose of this study was to investigate the effect of the muscle metaboreflex on hemodynamics following fatiguing rhythmic handgrip exercise and circulatory arrest in 10 male collegiate body builders and 10 age-matched controls. All subjects performed 3 min rhythmic handgrip exercise at the exercise intensity of 60% maximal voluntary contraction and 2 min of postexercise circulatory occlusion while heart rate (HR), stroke volume (SV), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured followed by the calculation of cardiac output, mean arterial pressure (MAP), and total vascular conductance (TVC). From resting baseline values, the changes in SBP, DBP, and MAP in body builders during PEI were significantly smaller compared to contol group (SBP: △ 31.2 mmHg vs. △ 36.2 mmHg; DBP: △ 9.9 mmHg vs. △ 18.2 mmHg; MAP: △ 17.0 mmHg vs. △ 24.2 mmHg, respectively). However, there was no difference in CO between two groups (△ 2.2 l/min vs. △ 2.2 l/min) and TVC tended to be higher in body builders compared to control group (△ 9.0 ml/min/mmHg vs. △ 3.9 ml/min/mmHg). This study suggest that chronic resistance training may improve the muscle metaboreflex. The mechanism in which the pressor response mediated by the muscle metaboreflex with resistance training is attenuated is due to peripheral vasodilation.
Previous studies have shown that resistive exercise training such as isometric handgrip exercise or weightlifting decreases arterial blood pressure. However, the mechanisms responsible for reduction in arterial blood pressure have not been investigated. One mechanism that may lower arterial blood pressure is a neural mechanism termed the muscle metaboreflex that is activated when oxygen delivery to active skeletal muscle falls below a critical level. The muscle metaboreflex, a component of exercise pressor reflex, increases the sympathetic activity to heart and vasculature and then increases arterial blood pressure, cardiac output, and ventilation during exercise. Therefore, the purpose of this study was to investigate the effect of the muscle metaboreflex on hemodynamics following fatiguing rhythmic handgrip exercise and circulatory arrest in 10 male collegiate body builders and 10 age-matched controls. All subjects performed 3 min rhythmic handgrip exercise at the exercise intensity of 60% maximal voluntary contraction and 2 min of postexercise circulatory occlusion while heart rate (HR), stroke volume (SV), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured followed by the calculation of cardiac output, mean arterial pressure (MAP), and total vascular conductance (TVC). From resting baseline values, the changes in SBP, DBP, and MAP in body builders during PEI were significantly smaller compared to contol group (SBP: △ 31.2 mmHg vs. △ 36.2 mmHg; DBP: △ 9.9 mmHg vs. △ 18.2 mmHg; MAP: △ 17.0 mmHg vs. △ 24.2 mmHg, respectively). However, there was no difference in CO between two groups (△ 2.2 l/min vs. △ 2.2 l/min) and TVC tended to be higher in body builders compared to control group (△ 9.0 ml/min/mmHg vs. △ 3.9 ml/min/mmHg). This study suggest that chronic resistance training may improve the muscle metaboreflex. The mechanism in which the pressor response mediated by the muscle metaboreflex with resistance training is attenuated is due to peripheral vasodilation.