Reduced exercise capacity in senescent beagles: an evaluation of the periphery.
Reduced exercise capacity in senescent beagles: an evaluation of the periphery.
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衰老比格犬的运动能力下降：外围评估。
DOI：
10.1152/ajpheart.1991.260.1.h173
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Parsons,D
中科院分区：
文献类型：
--
作者：
Haidet,GC;Parsons,D
本研究探讨了年龄对最大运动全身反应的外周因素的影响。分析了骨骼肌，并在休息时和最大运动期间确定区域血流分布在衰老（老）和年轻成熟（年轻）比格犬。老年人的最大运动能力显著降低（P <0.05），并与心输出量（CO）降低以及动静脉O2差降低的趋势相关，同时最大O2消耗量降低。在评估的每个区域循环中，年轻人和老年人的静息血流量相似。在运动过程中，年轻人和老年人的横膈膜、心脏、舌头和七块运动肌肉中的六块的血流量是相似的。伴随的内脏区域的血流减少往往是更明显的老年人比年轻。肱三头肌，半腱肌，腓肠肌骨骼肌分析揭示了类似的百分比纤维类型分布在年轻人和老年人，但减少II型纤维面积在老年人。此外，肌肉毛细血管密度和毛细血管与纤维的比率都降低，在老年人。这些结果表明，年龄相关的变化，在最大的运动过程中的血流分布，使骨骼肌血流量保持在老，尽管减少最大CO和肌肉毛细血管密度。然而，这种模式的血流分布只能部分补偿年龄相关的外周代谢潜力的变化，动脉血中的O2含量，和心脏功能在老年人的最大运动的综合影响。
This study investigated the effect of age on peripheral factors involved in the systemic response to maximal exercise. Skeletal muscle was analyzed and regional blood flow distribution was determined at rest and during maximal exercise in senescent (old) and in younger mature (young) beagles. Maximal exercise capacity was significantly reduced (P less than 0.05) in old and was associated with a reduction in cardiac output (CO), as well as a tendency for arteriovenous O2 difference to be reduced, with a concomitant reduction in maximal O2 consumption. In each regional circulation evaluated, resting blood flow was similar in young and old. During exercise, blood flow was similar in young and old to the diaphragm, heart, tongue, and six of seven locomotory muscles. Concomitant blood flow reductions in splanchnic regions tended to be more pronounced in old than in young. Skeletal muscle analyses of triceps, semitendinosus, and gastrocnemius muscles disclosed similar percent fiber type distribution in young and old but a reduction in type II fiber area in old. In addition, both muscle capillary density and capillary-to-fiber ratio were reduced in old. These results demonstrate that age-related changes in blood flow distribution during maximal exercise enable skeletal muscle blood flow to be maintained in old, despite reductions in maximal CO and in muscle capillary density. However, this pattern of blood flow distribution only partially compensates for the combined effects of age-related changes in metabolic potential of the periphery, O2 content of arterial blood, and cardiac function during maximal exercise in old.