Novak Vera, Hu Kun, Vyas Mitul, Lipsitz Lewis A
Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
J Gerontol A Biol Sci Med Sci. 2007 Jan;62(1):86-92. doi: 10.1093/gerona/62.1.86.
Walking is a complex act that requires the coordination of locomotor, cardiovascular, and autonomic systems. Aging affects each of these systems and may alter physiological mechanisms regulating the interactions between them.
We examined the effects of healthy aging on cardiac-locomotor coupling using treadmill walking at incremental speeds from 0.8 mph to normal walking speed in 12 healthy young (29.0 +/- 5.0 years) and 9 healthy elderly persons (70.3 +/- 5.1 years). interbeat (R-R) intervals, step intervals, maximum foot pressure (MFP) and normalized maximum force, blood pressure (BP), and blood flow velocity (BFV) in the middle cerebral artery were continuously measured.
Step intervals and R-R intervals decreased, and MFP and BFV increased with walking speed in both groups; systolic BP increased (p <.0001) in the old group. In elderly, but not in young participants, step intervals and R-R intervals were coupled (R(2) = 0.84, p <.0001), and MFP was correlated with systolic BP (R(2) = 0.51, p <.02).
Cardiolocomotor coupling that becomes manifest with aging may optimize cardiovascular responses during walking. In elderly people, forces generated during the gait cycle may be transmitted to arterial pressure and thus synchronize the central cardiovascular network with the stepping rhythm.
行走是一种复杂的行为，需要运动、心血管和自主神经系统的协调。衰老会影响这些系统中的每一个，并可能改变调节它们之间相互作用的生理机制。
我们以0.8英里/小时至正常步行速度的递增速度在跑步机上行走，研究健康衰老对心脏-运动耦合的影响，研究对象为12名健康年轻人（29.0±5.0岁）和9名健康老年人（70.3±5.1岁）。连续测量心间（R-R）间期、步幅间期、最大足底压力（MFP）和标准化最大力、血压（BP）以及大脑中动脉的血流速度（BFV）。
两组的步幅间期和R-R间期均随步行速度降低，MFP和BFV随步行速度增加；老年组收缩压升高（p<.0001）。在老年人中，而非年轻人中，步幅间期和R-R间期存在耦合（R² = 0.84，p<.0001），且MFP与收缩压相关（R² = 0.51，p<.02）。
随着衰老而显现的心脏-运动耦合可能会优化行走过程中的心血管反应。在老年人中，步态周期中产生的力可能会传递到动脉血压，从而使中枢心血管网络与步幅节奏同步。
