Harper Allison J, Ferreira Leonardo F, Lutjemeier Barbara J, Townsend Dana K, Barstow Thomas J
Department of Kinesiology, 1A Natatorium, Kansas State University, Manhattan, KA 66506-0302, USA.
Exp Physiol. 2008 Oct;93(10):1118-25. doi: 10.1113/expphysiol.2008.042895. Epub 2008 May 30.
It is unclear whether measurement of limb or conduit artery blood flow during recovery from exercise provides an accurate representation of flow to the muscle capillaries where gas exchange occurs. To investigate this, we: (a) examined the kinetic responses of femoral artery blood flow (QFA), estimated muscle capillary blood flow (Qcap) and estimated muscle oxygen uptake (VO2m) following cessation of exercise; and (b) compared these responses to verify the adequacy of O2 delivery during recovery. Pulmonary VO2 (VO2p) was measured breath by breath, QFA was measured using Doppler ultrasonography, and deoxy-haemoglobin/myoglobin (deoxy-[Hb/Mb]) was estimated by near-infrared spectroscopy over the rectus femoris in nine healthy subjects during a series of transitions from moderate knee-extension exercise to rest. The time course of Qcap was estimated by rearranging the Fick equation [i.e. Qcap(t) alpha VO2m(t)/deoxy-Hb/Mb], using the primary component of Vo2p to represent VO2m and deoxy-[Hb/Mb] as a surrogate for arteriovenous O2 difference. There were no significant differences among the overall kinetics of VO2m (tau, 31.4+/-8.2 s), QFA [mean response time (MRT), 34.5+/-20.4 s] and Qcap (MRT, 31.7+/-14.7 s). The VO2m kinetics were also significantly correlated (P<0.05) with those of both QFA and Qcap. Both QFA and Qcap appear to be coupled with VO2m during recovery from moderate knee-extension exercise, such that extraction falls (thus cellular energetic state is not further compromised) throughout recovery.
目前尚不清楚在运动恢复过程中测量肢体动脉或导管动脉血流是否能准确反映气体交换发生部位——肌肉毛细血管的血流情况。为了研究这一问题，我们：(a) 研究了运动停止后股动脉血流（QFA）、估计的肌肉毛细血管血流（Qcap）和估计的肌肉摄氧量（VO2m）的动力学反应；(b) 比较这些反应以验证恢复过程中氧气输送的充足性。在9名健康受试者从适度的膝关节伸展运动过渡到休息的一系列过程中，逐次测量肺VO2（VO2p），使用多普勒超声测量QFA，并通过近红外光谱法估计股直肌中的脱氧血红蛋白/肌红蛋白（脱氧-[Hb/Mb]）。通过重新排列菲克方程 [即Qcap(t) α VO2m(t)/脱氧-Hb/Mb] 来估计Qcap的时间进程，使用VO2p的主要成分代表VO2m，并将脱氧-[Hb/Mb] 作为动静脉氧分压差的替代指标。VO2m（τ，31.4±8.2秒）、QFA [平均反应时间（MRT），34.5±20.4秒] 和Qcap（MRT，31.7±14.7秒）的总体动力学之间没有显著差异。VO2m的动力学也与QFA和Qcap的动力学显著相关（P<0.05）。在从适度的膝关节伸展运动恢复过程中，QFA和Qcap似乎都与VO2m耦合，因此在整个恢复过程中摄取量下降（从而细胞能量状态不会进一步受损）。
