White M J, Carrington C A
Applied Physiology Research Unit, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, England.
Eur J Appl Physiol Occup Physiol. 1993;66(4):338-42. doi: 10.1007/BF00237779.
Changes in heart rate (fc) and blood pressure (BP) were observed in eight healthy young men aged [mean (SD)] 20 (1) years and ten healthy elderly men aged 65 (5) years, during electrically evoked contractions of the ankle plantar flexors and elbow flexors which were sustained for 2 min. There was no significant difference in the fc response to evoked contraction of the ankle plantar flexors or elbow flexors between young and elderly subjects. During contraction of the elbow flexors, elderly subjects produced an unexpectedly large rise in systolic BP which was significantly greater than that of the young subjects. The exaggerated response seen in the elderly group may be due to a more rigid arterial tree which is thought to occur with advancing age. Electrically evoked contraction of the slower contracting elderly ankle plantar flexors resulted in a significantly diminished diastolic BP response when compared with that of the young subjects. In contrast, during electrically evoked contraction of the elbow flexors, which showed a similar twitch time course in young and elderly subjects, the diastolic BP response was not significantly different between groups. This may reflect differences in the peripheral reflex input to the pressor response in elderly arm and leg muscles which, in turn, may be influenced by relative fast twitch fibre area.
在8名平均（标准差）年龄为20（1）岁的健康年轻男性和10名平均年龄为65（5）岁的健康老年男性中，观察了在持续2分钟的踝关节跖屈肌和肘关节屈肌电诱发收缩期间心率（fc）和血压（BP）的变化。年轻受试者和老年受试者对踝关节跖屈肌或肘关节屈肌诱发收缩的fc反应没有显著差异。在肘关节屈肌收缩期间，老年受试者的收缩压意外大幅升高，显著高于年轻受试者。老年组中出现的这种夸张反应可能是由于随着年龄增长动脉树变得更加僵硬所致。与年轻受试者相比，收缩较慢的老年踝关节跖屈肌的电诱发收缩导致舒张压反应显著降低。相比之下，在年轻和老年受试者中抽搐时间过程相似的肘关节屈肌电诱发收缩期间，两组之间的舒张压反应没有显著差异。这可能反映了老年手臂和腿部肌肉对压力反应的外周反射输入的差异，而这反过来可能受相对快肌纤维面积的影响。
