比較正常與過重大學生運動中腦氧合及血液動態學差異

Abstract

背景: 肥胖對於心血管功能有負面影響，可能會造成運動中心血管及腦氧不同的反應，過去少有研究比較肥胖和正常學生在運動中血液動態學與腦氧合的表現。本研究目的:(一)比較過重大學生與正常組於最大運動測試中腦氧合與血液動態學的差異。(二)比較正常體重與過重大學生於單次30分鐘高強度有氧運動中腦氧合與血液動態學的變化的差異。研究方法: 招募過重組大學男生14名(平均BMI29.0±5.4 kg/m2) 與正常組18名(平均BMI22.4±1.4 kg/m2 ) 進行腳踏車最大運動測試，測量最大攝氧量("Ṽ" O2max)和最大作功率。相隔一週後再從事30分鐘 (70% max workload, Wmax,最大作功負荷)之有氧運動。以生物電阻阻抗儀(Physioflow)測量兩次運動中血液動態學之心輸出量( CO)、心搏量(SV)、射血比(EF)，以近紅外線光譜儀來測量腦部氧合(含氧血紅素, O2Hb)、去氧血紅素(HHb)和總血紅素( tHb)。統計分析: 所得資料以二因子變異數分析兩組血液動態學和腦氧合狀態差異。結果: 最大運動測試中，正常組之"Ṽ" O2max顯著大於過重組(41.3±5.7與30.0±5.0) ml/min/kg，p<0.05)。正常組CO從安靜時5.7±1.2L顯著增加至100%Wmax時19.2±4.1L (p<0.05)；過重組的CO從安靜時6.9±1.3L 增加至100%Wmax時 20.4±4.4L (p<0.05)。兩組組間CO表現無顯著差異，但正常組在70%Wmax時CO增加幅度(179.8%)顯著大於過重組(137.0%) (p<0.05)。運動測試中，正常組腦tHb從安靜至50%Wmax共增加(7.0um)，顯著大於過重組(1.7um)( p<0.05)。單次有氧運動中，兩組血液動態學無顯著差異，但運動中第10、20、30分鐘，正常組CO分別增加幅度為178.8%、199.3%、219.4%，顯著大於過重組105.8%、121.0%、130.0% (p<0.05)。運動停止後20分鐘，正常組腦部O2Hb增加13.9um，顯著大於過重組(1.0um) (p<0.05)。結論: 過重大學生於激烈運動時心輸出量和恢復其腦部供氧量增加幅度較正常體重組少。過重大學生從事激烈運動時應注意這些生理反應。BACKGROUND: Obesity has a negative impact on cardiovascular function that may increase the risk during exercise. Few studies have investigated the hemodynamics and cerebral oxygenation in this area. The purposes of this study are (a) to compare the hemodynamic and cerebral oxygen changes during maximal exercise test between overweight(OS) and normal weight students(NS). (b) to compare the hemodynamic and cerebral oxygenation changes during vigorous exercise between OS and NS. METHODS: Eighteen maleNS college students (mean BMI29.0±5.4 kg/m2 ) and 14 OS (mean BMI22.4±1.4 kg/m2) were recruited and asked to perform maximal exercise test on ergometer to measure maximum oxygen uptake ("Ṽ" O2max) and maximum power. One week later, subjects had performed a high intensity (70% max workload, Wmax) cycling exercise for 30 min. The hemodynamics CO, SV, EF of all subjects during exercises were measured with a bioelectrical impedance device (Physioflow), and cerebral oxygenation status (oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), total hemoglobin (tHb) was measured by a near infrared spectrophotometer (NIRS). STATISTICS: The collected data were analyzed with 2-way ANOVA. RESULTS: The "Ṽ" O2max of NS was significantly higher than that of OS (41.3±5.7 vs 30.0 ±5.0 ml / min / kg, p<0.05). The CO of NS was significantly increased from resting status ( 5.7 ±1.2L) to 100% Wmax (19.2 ±4.1 L) (p<0.05) in the NS, and 6.9±1.3 L to 20.4±4.4 L (p<0.05) of OS. There were no significant differences of CO between the two groups, but CO increase179.8% in 70% Wmax in NS was significantly greater than that of the OS (137.0%) (p <0.05). The cerebral tHb of NS increased (7.0um) at 50% Wmax significantly greater than that (1.7um) of OS (p <0.05). During 30 min vigorous exercise, there wasno significant difference in hemodynamics between the two groups (p> .05). During 10,20,30 minutes, the CO increases of NS (178.8%, 199.3%, 219.4%) were significantly higher than that of the OS (105.8% ,121% and 130%, respectively) (p<0.05). There was no significant difference of cerebral oxygenation between the two groups during endurance exercise. But the O2Hb of NS at 20 minutes of endurance exercise, increased 13.9um was significantly higher than that of the OS (1.0um ) (p <0.05). CONCLUSION: The overweight college students showed less cardiac output and cerebral oxygenation than that of NS during vigorous exercise and recovery. These physiological response may take into consideration while engage in vigorous exercise.