單次不同強度阻力運動對於年輕健康男性微血管功能之影響

背景：隨著國內心血管疾病盛行率有年輕化的趨勢，除了飲食控制外規律運動也成為預防心血管疾病重要的手段。血管內皮為單層扁平細胞附著於血管內壁上，其功能為調節體內血流，先前研究發現動脈血管內皮細胞功能異常 (endothelial dysfunction) 為罹患心血管疾病的重要風險因子。已有文獻指出長期阻力訓練可以改善血管內皮細胞功能進而降低患病風險，然而現階段阻力運動對於血管功能的影響未有一致結果，尚待闡明。目的：探討健康年輕男性進行不同強度單次阻力運動血管功能以及組織耗氧量之差異。方法：本研究篩選健康年輕男性11名作為受試者，進行單次高與低強度阻力運動或靜坐，並分別抽取介入前後之血液樣本，以分析氮氧化物 (nitrate/nitrite, NOx), 內皮素-1 (endothelin-1, ET-1) 血管功能生化指標，同時利用近紅外線光譜儀血流阻斷測試 (near infrared spectroscopy-vascular occlusion test, NIRS-VOT) 測量微血管功能、肌肉組織含氧量指標。研究數據採用混合線性模型分析 (linear mixed model, LMM) 進行考驗，以驗證其差異性。結果：一、生理以及血液生化指標相關數值，高強度與低強度運動介入後立即以及 60 分血乳酸濃度顯著高於控制介入 (p < .05)；低強度運動介入後立即 NOx 濃度變化量顯著高於控制介入 (p < .05)；血壓數值以及ET-1濃度於不同介入下並無顯著差異 (p > .05)。二、組織含氧量相關數值，Baseline StO2變化量於高強度運動介入後立即顯著高於控制介入 (p <. 05)；Minimum StO2以及slope 1 數值介入間無顯著差異 (p >.05)。三、血管功能相關指標數值，AUC以及slope 2 數值介入間無顯著差異 (p > .05)。相關性分析結果顯示AUC與slope 2數值呈顯著正相關，而Minimum StO2與slope 2、血乳酸濃度與slope 1數值呈顯著負相關。結論：一、年輕健康男性於不同強度阻力運動介入後，皆觀察到肌肉組織耗氧量Minimum StO2以及slope 1數值呈下降之趨勢，推測為肌肉組織進行乳酸代謝及磷酸肌酸系統回補有關。低強度阻力運動後，NOx濃度顯著上升，為肌肉反覆收縮使血流刺激內皮細胞增加NO分泌量所致。單次不同強度阻力運動後血壓無顯著上升，因此血管功能指標slope 2數值並未受損；AUC數值與長期運動微血管適應性較為相關，因此單次運動介入無法觀察到數值變化。二、現階段NIRS-VOT之檢測方法以及干擾因素，尚需更多運動相關研究，以釐清各數值所代表之生理意義。

關鍵字

心血管疾病；血管功能；血管內皮細胞；阻力運動

並列摘要

Introduction: As there is growing trend of younger age group suffering cardiovascular event in Taiwan, regular exercise has become an important method to prevent cardiovascular disease (CVD) apart from diet control. The endothelial cells are a single-layer cell locating on the inner side of the vascular wall, which play a crucial role of regulating vascular blood flow. Previous articles showed that endothelial dysfunction could be a major indicator of CVD. Recent studies confirmed that regular resistance training could improve vascular function, and lower the risk of CVD. However, the acute effect of resistance exercise on endothelial function is inconclusive. Purpose: The present study investigates endothelial function and muscle oxygen saturation in healthy young men after a single session of resistance exercise at different intensities. Methods: Eleven healthy young men underwent three different conditions of assessment: (1) whole body resistance exercise at high intensity (4 sets of 8 repetitions at 85% of 8RM), (2) whole body resistance exercise at low intensity (4 sets of 15 repetitions at 45% of 8RM), (3) resting for the control condition. Vascular function and muscle oxygen saturation were assessed by NIRS-VOT before, immediately and 60 min after exercise. Blood pressure (BP), plasma concentrations of endothelin-1 (ET-1), nitrite and nitrate (NOx) and lactate were measured before, immediately and 60 min after exercise. Results: Lactate concentration was significantly higher immediately and 60 min after high and low intensity resistance exercise compared to control condition (p < .05). Changes in NOx levels were significantly higher immediately after low intensity resistance exercise (p < .05). Additionally, there was a significant increase in Baseline StO2 immediately after high intensity resistance exercise (p < .05). However, there was no significant difference for ET-1, BP, Minimum StO2, slope 2 and AUC among the experimental conditions. Conclusion: Our findings showed: (1) the downward trend of Minimum StO2 and slope 1 after two different resistance exercise intensities in healthy young men, could be caused by replenishment of phosphagen system and lactate metabolism. The significant increase of plasma NOx levels, released by endothelial cells was probably due to high frequency of muscle contraction during low intensity resistance exercise. In addition, there was no significant for slope 2 and AUC, which was mainly due to no change of BP value and the lack of vascular adaptation after a single session of resistance exercise. (2) NIRS-VOT, as an alternative technique assessing vascular function and muscle oxygen saturation, still has some issue and limitation needed further research to clarify.

並列關鍵字

cardiovascular disease ； vascular function ； vascular endothelium ； resistance exercise

參考文獻

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