Takahashi Tatsuhisa, Hayano Junichiro, Okada Akiyoshi, Saitoh Tadashi, Kamiya Akira
Department of Mathematical Information Science, Asahikawa Medical College, Asahikawa 078-8510, Japan.
Eur J Appl Physiol. 2005 Aug;94(5-6):576-83. doi: 10.1007/s00421-005-1369-5. Epub 2005 Jun 1.
The purpose of the study was to characterize the effects of muscular contractions (the muscle pump) and body posture on cardiovascular responses during recovery from moderate exercise in the upright-sitting or supine positions. Heart rate (HR), stroke volume (SV), and cardiac output (CO) were measured in seven young male subjects at rest and during 10-min of cycle exercise at 60% of peak oxygen uptake (VO2peak). This was followed by either complete rest for 5 min (inactive recovery) or cycling at VO2peak for 5 min (active recovery) in the upright or supine positions. In the upright position, an initial rapid decrease in HR was followed by a gradual decrease in HR, and this response was similar when comparing inactive and active recoveries. Upright SV during inactive recovery decreased gradually to the pre-exercise resting level, whereas upright SV during active recovery remained significantly elevated. In contrast, in the supine position, the HR during active recovery decreased, but remained significantly higher than that during inactive recovery. Changes in supine SV were similar when comparing inactive and active recovery. Thus, maintenance of SV and HR resulted in significantly greater CO during active recovery than during inactive recovery, regardless of body position. HR was greater during supine active-recovery than during supine inactive-recovery, and there was no difference in SV. These data suggest that the muscle pump is less important in facilitating venous return and vagal resumption in the supine position as compared to the upright position.
本研究的目的是描述肌肉收缩（肌肉泵）和身体姿势对直立坐姿或仰卧位中度运动恢复期间心血管反应的影响。在7名年轻男性受试者休息时以及在以峰值摄氧量（VO2peak）的60%进行10分钟的自行车运动期间，测量心率（HR）、每搏输出量（SV）和心输出量（CO）。随后，受试者在直立或仰卧位进行5分钟的完全休息（非活动恢复）或在VO2peak下进行5分钟的自行车运动（活动恢复）。在直立位时，HR最初迅速下降，随后逐渐下降，在比较非活动恢复和活动恢复时，这种反应相似。非活动恢复期间直立位的SV逐渐降至运动前的静息水平，而活动恢复期间直立位的SV仍显著升高。相比之下，在仰卧位时，活动恢复期间的HR下降，但仍显著高于非活动恢复期间。比较非活动恢复和活动恢复时，仰卧位SV的变化相似。因此，无论身体姿势如何，活动恢复期间维持SV和HR导致的心输出量显著高于非活动恢复期间。仰卧位活动恢复期间的HR高于仰卧位非活动恢复期间，且SV无差异。这些数据表明，与直立位相比，肌肉泵在促进仰卧位静脉回流和迷走神经恢复方面的重要性较低。
