Chantler Paul D, Clements R E, Sharp L, George K P, Tan L-B, Goldspink D F
Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, UK.
Am J Physiol Heart Circ Physiol. 2005 Nov;289(5):H2059-65. doi: 10.1152/ajpheart.00022.2005. Epub 2005 Jun 17.
The purpose of this study was to determine the best scaling method to account for the effects of body size on measurements of overall cardiac function and subsequently the interpretation of data based on cardiac power output (CPO). CPO was measured at rest (CPO(rest)) and at maximal exercise (CPO(max)) on 88 and 103 healthy but untrained men and women, respectively, over the age range of 20-70 yr. Cardiac reserve (CR) was calculated as CPO(max) - CPO(rest). CPO(rest), CPO(max), and CR were all significantly related to body mass (BM), body surface area (BSA), and lean body mass (LBM). The linear regression model failed to completely normalize these measurements. In contrast, the allometric model produced size-independent values of CPO. Furthermore, all the assumptions associated with the allometric model were achieved. For CPO(rest), mean body size exponents were BM(0.33), BSA(0.60), and LBM(0.47). For CPO(max), the exponents were BM(0.41), BSA(0.81), and LBM(0.71). For CR, mean body size exponents were BM(0.44), BSA(0.87), and LBM(0.79). LBM was identified (from the root-mean-squares errors of the separate regression models) as the best physiological variable (based on its high metabolic activity) to be scaled in the allometric model. Scaling of CPO to LBM(b) (where b is the scaling exponent) dramatically reduced the between-gender differences with only a 7% difference in CPO(rest) and CPO(max) values. In addition, the gender difference in CR was completely removed. To avoid erroneous interpretations and conclusions being made when comparing data between men and women of different ages, the allometric scaling of CPO to LBM(b) would seem crucial.
本研究的目的是确定最佳的标度方法，以考虑身体大小对整体心脏功能测量的影响，并随后基于心脏功率输出（CPO）对数据进行解释。分别在20至70岁的88名健康但未经训练的男性和103名健康但未经训练的女性中，测量静息状态下（CPO(rest)）和最大运动时（CPO(max)）的CPO。心脏储备（CR）计算为CPO(max) - CPO(rest)。CPO(rest)、CPO(max)和CR均与体重（BM）、体表面积（BSA）和去脂体重（LBM）显著相关。线性回归模型未能完全使这些测量值标准化。相比之下，异速生长模型产生了与大小无关的CPO值。此外，与异速生长模型相关的所有假设均得到满足。对于CPO(rest)，平均身体大小指数为BM(上标0.33)、BSA(上标0.60)和LBM(上标0.47)。对于CPO(max)，指数为BM(上标0.41)、BSA(上标0.81)和LBM(上标0.71)。对于CR，平均身体大小指数为BM(上标0.44)、BSA(上标0.87)和LBM(上标0.79)。（从单独回归模型的均方根误差中）确定LBM是异速生长模型中要进行标度的最佳生理变量（基于其高代谢活性）。将CPO标度为LBM(b)（其中b是标度指数）显著降低了性别差异，CPO(rest)和CPO(max)值的差异仅为7%。此外完全消除了CR中的性别差异。为避免在比较不同年龄的男性和女性的数据时产生错误的解释和结论，将CPO进行异速生长标度为LBM(b)似乎至关重要。
