Poole David, Behnke Brad, Musch Timothy
Departments of Anatomy, Physiology and Kinesiology, Kansas State University, Manhattan, Kansas, USA.
Microcirculation. 2006 Jun;13(4):289-99. doi: 10.1080/10739680600618793.
Healthy aging acts to redistribute blood flow (Q) and thus O2 delivery (QO2 ) among and within the exercising muscles such that QO2 to highly oxidative muscle fibers may be compromised. Within the microcirculation of old muscles capillary hemodynamics are altered and the matching of QO2 to oxidative requirements (VO2) is impaired such that at exercise onset the microvascular O2 pressure falls below that seen in their younger counterparts. This is important because the microvascular O2 pressure denotes the sole driving force for blood-myocyte O2 transfer and any compromise may slow VO2 kinetics and reduce exercise tolerance. This review considers the microcirculatory evidence for a reduced perfusive (QO2 ) and diffusive O2 flux within aged muscle and highlights the pressing need for intravital microscopy studies of the muscle microcirculation during exercise.
健康衰老会重新分配血流量（Q），进而在运动肌肉之间及内部重新分配氧气输送量（QO2），使得流向高氧化肌纤维的QO2可能会受到影响。在老年肌肉的微循环中，毛细血管血流动力学发生改变，QO2与氧化需求（VO2）的匹配受损，以至于在运动开始时，微血管氧气压力低于年轻肌肉中的水平。这一点很重要，因为微血管氧气压力是血液与心肌细胞间氧气转移的唯一驱动力，任何影响都可能减慢VO2动力学并降低运动耐力。本综述探讨了老年肌肉内灌注性（QO2）和扩散性氧气通量降低的微循环证据，并强调了对运动期间肌肉微循环进行活体显微镜研究的迫切需求。
