| Summary: | 博士 === 國立臺灣師範大學 === 體育學系 === 105 === 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 male NS 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 was no 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.
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