Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Wickenden Bldg. Rm 524, Cleveland, OH 44106-7207, USA.
Eur J Appl Physiol. 2012 Mar;112(3):973-82. doi: 10.1007/s00421-011-2054-5. Epub 2011 Jun 30.
The effect of exercise intensity on the on- and off-transient kinetics of oxygen uptake (VO(2)) was investigated in African American (AA) and Caucasian (C) women. African American (n = 7) and Caucasian (n = 6) women of similar age, body mass index and weight, performed an incremental test and bouts of square-wave exercise at moderate, heavy and very heavy intensities on a cycle ergometer. Gas exchange threshold (LT(GE)) was lower in AA (13.6 ± 2.3 mL kg(-1) min(-1)) than C (18.6 ± 5.6 mL kg(-1) min(-1)). The dynamic exercise and recovery VO(2) responses were characterized by mathematical models. There were no significant differences in (1) peak oxygen uptake (VO(2peak)) between AA (28.5 ± 5 mL kg(-1) min(-1)) and C (31.1 ± 6.6 mL kg(-1) min(-1)) and (2) VO(2) kinetics at any exercise intensity. At moderate exercise, the on- and off- VO(2) kinetics was described by a monoexponential function with similar time constants τ (1,on) (39.4 ± 12.5; 38.8 ± 15 s) and τ (1,off) (52.7 ± 10.1; 40.7 ± 4.4 s) for AA and C, respectively. At heavy and very heavy exercise, the VO(2) kinetics was described by a double-exponential function. The parameter values for heavy and very heavy exercise in the AA group were, respectively: τ (1,on) (47.0 ± 10.8; 44.3 ± 10 s), τ (2,on) (289 ± 63; 219 ± 90 s), τ (1,off) (45.9 ± 6.2; 50.7 ± 10 s), τ (2,off) (259 ± 120; 243 ± 93 s) while in the C group were, respectively: τ (1,on) (41 ± 12; 43.2 ± 15 s); τ (2, on) (277 ± 81; 215 ± 36 s), τ (1,off) (40.2 ± 3.4; 42.3 ± 7.2 s), τ (2,off) (215 ± 133; 228 ± 64 s). The on- and off-transients were symmetrical with respect to model order and dependent on exercise intensity regardless of race. Despite similar VO(2) kinetics, LT(GE) and gain of the VO(2) on-kinetics at moderate intensity were lower in AA than C. However, generalization to the African American and Caucasian populations is constrained by the small subject numbers.
研究了运动强度对非洲裔美国（AA）和白种人（C）女性摄氧量（VO2）的瞬态动力学的影响。 7 名非裔美国人和 6 名白种人女性，年龄、体重指数和体重相似，在自行车测力计上进行了递增测试和中等、大强度和极高强度的方波运动。非裔美国人（AA）的气体交换阈值（LT（GE））低于白种人（13.6 ± 2.3 mL kg（-1）min（-1））（18.6 ± 5.6 mL kg（-1）min（-1））。 动态运动和恢复的 VO2 反应由数学模型描述。在任何运动强度下，（1）峰值摄氧量（VO2peak），AA（28.5 ± 5 mL kg（-1）min（-1））和 C（31.1 ± 6.6 mL kg（-1）min（-1））之间没有显著差异；（2） VO2 动力学。在中等运动强度下，ON 和 OFF 的 VO2 动力学由单指数函数描述，AA 和 C 的 τ（1，ON）（39.4 ± 12.5；38.8 ± 15 s）和 τ（1，OFF）（52.7 ± 10.1；40.7 ± 4.4 s）的时间常数相似。在大强度和极高强度运动时，VO2 动力学由双指数函数描述。AA 组的大强度和极高强度运动的参数值分别为：τ（1，ON）（47.0 ± 10.8；44.3 ± 10 s），τ（2，ON）（289 ± 63；219 ± 90 s），τ（1，OFF）（45.9 ± 6.2；50.7 ± 10 s），τ（2，OFF）（259 ± 120；243 ± 93 s），而 C 组分别为：τ（1，ON）（41 ± 12；43.2 ± 15 s）；τ（2，ON）（277 ± 81；215 ± 36 s），τ（1，OFF）（40.2 ± 3.4；42.3 ± 7.2 s），τ（2，OFF）（215 ± 133；228 ± 64 s）。ON 和 OFF 瞬变相对于模型阶数是对称的，并且与种族无关，取决于运动强度。尽管 VO2 动力学相似，但 AA 在中等强度下的 LT（GE）和 VO2 的初始上升动力学增益均低于 C。然而，由于受试者数量较少，对非裔美国人和白种人群体的推广受到限制。
