Proctor D N, Beck K C, Shen P H, Eickhoff T J, Halliwill J R, Joyner M J
Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
J Appl Physiol (1985). 1998 Feb;84(2):599-605. doi: 10.1152/jappl.1998.84.2.599.
It is presently unclear how gender, aging, and physical activity status interact to determine the magnitude of the rise in cardiac output (Qc) during dynamic exercise. To clarify this issue, the present study examined the Qc-O2 uptake (Vo2) relationship during graded leg cycle ergometry in 30 chronically endurance-trained subjects from four groups (n = 6-8/group): younger men (20-30 yr), older men (56-72 yr), younger women (24-31 yr), and older women (51-72 yr). Qc (acetylene rebreathing), stroke volume (Qc/heart rate), and whole body Vo2 were measured at rest and during submaximal exercise intensities (40, 70, and approximately 90% of peak Vo2). Baseline resting levels of Qc were 0.6-1.2 l/min less in the older groups. However, the slopes of the Qc-Vo2 relationship across submaximal levels of cycling were similar among all four groups (5.4-5.9 l/l). The absolute Qc associated with a given Vo2 (1.0-2.0 l/min) was also similar among groups. Resting and exercise stroke volumes (ml/beat) were lower in women than in men but did not differ among age groups. However, older men and women showed a reduced ability, relative to their younger counterparts, to maintain stroke volume at exercise intensities above 70% of peak Vo2. This latter effect was most prominent in the oldest women. These findings suggest that neither age nor gender has a significant impact on the Qc-Vo2 relationships during submaximal cycle ergometry among chronically endurance-trained individuals.
目前尚不清楚性别、衰老和身体活动状态如何相互作用，以确定动态运动期间心输出量（Qc）上升的幅度。为了阐明这个问题，本研究在30名来自四组（每组n = 6 - 8）长期耐力训练的受试者进行分级腿部循环测力计测试期间，研究了Qc与摄氧量（Vo2）的关系：年轻男性（20 - 30岁）、老年男性（56 - 72岁）、年轻女性（24 - 31岁）和老年女性（51 - 72岁）。在休息时以及次最大运动强度（峰值Vo2的40%、70%和约90%）期间测量Qc（乙炔重呼吸法）、每搏输出量（Qc/心率）和全身Vo2。老年组的基线静息Qc水平低0.6 - 1.2升/分钟。然而，在所有四组中，次最大骑行水平下Qc - Vo2关系的斜率相似（5.4 - 5.9升/升）。与给定Vo2（1.0 - 2.0升/分钟）相关的绝对Qc在各组之间也相似。女性的静息和运动每搏输出量（毫升/次）低于男性，但在年龄组之间没有差异。然而，相对于年轻同龄人，老年男性和女性在运动强度高于峰值Vo2的70%时，维持每搏输出量的能力降低。后一种效应在最年长的女性中最为明显。这些发现表明，在长期耐力训练的个体中，年龄和性别对次最大循环测力计测试期间的Qc - Vo2关系均无显著影响。
