Davis G M, Shephard R J
Department of Health, Physical Education and Recreation, University of North Texas, Denton 76203-3857.
Med Sci Sports Exerc. 1988 Oct;20(5):463-8.
Maximum and submaximum arm crank exercise performances were assessed in male paraplegics (PARA) with the purpose of comparing cardiovascular responses among individuals of highly active (A, N = 15) vs inactive (I, N = 15) lifestyles. The A PARAs (average VO2 peak during arm cranking 2.24 l.min-1) demonstrated a significantly higher maximal cardiorespiratory fitness compared to I subjects (average VO2 peak 1.56 l.min-1). During graded arm exertion, at exercise intensities approximating 45%, 57%, and 70% of VO2 peak, the active subjects developed cardiac outputs (assessed via CO2-rebreathing) ranging from 9.07 to 11.21 l.min-1; a 34-44% advantage relative to their inactive counterparts (6.30-8.36 l.min-1). Similarly, exercise stroke volumes for A (76-80 ml) were 38-45% higher than for I paraplegics (55-56 ml). Although both groups demonstrated a distinctive circulatory hypokinesis during arm cranking, the immediate pattern of cardiovascular response was dissimilar for the highly active versus inactive subjects. The former demonstrated a predominantly "central" adaptation to steady-state arm exercise (exhibiting normal stroke volumes and arteriovenous O2 extractions for spinal cord-injured subjects), while the latter displayed markedly reduced stroke volumes concomitant with abnormally large peripheral arteriovenous oxygen extractions for a given oxygen uptake.
对男性截瘫患者（PARA）的最大和次最大手臂曲柄运动表现进行了评估，目的是比较高活动水平（A组，N = 15）与低活动水平（I组，N = 15）生活方式个体之间的心血管反应。A组截瘫患者（手臂曲柄运动期间平均最大摄氧量为2.24 l·min⁻¹）与I组受试者（平均最大摄氧量为1.56 l·min⁻¹）相比，表现出显著更高的最大心肺适能。在分级手臂用力过程中，当运动强度接近最大摄氧量的45%、57%和70%时，活跃受试者的心输出量（通过二氧化碳重呼吸法评估）范围为9.07至11.21 l·min⁻¹；相对于不活跃的对应受试者（6.30 - 8.36 l·min⁻¹）有34 - 44%的优势。同样，A组的运动每搏输出量（76 - 80 ml）比I组截瘫患者（55 - 56 ml）高38 - 45%。尽管两组在手臂曲柄运动期间都表现出明显的循环运动功能减退，但高活动水平与低活动水平受试者的心血管反应即时模式不同。前者在稳态手臂运动中表现出主要的“中枢”适应性（脊髓损伤受试者的每搏输出量和动静脉氧提取正常），而后者在给定摄氧量下每搏输出量明显降低，同时外周动静脉氧提取异常增大。
