Rassler B, Kohl J
Carl Ludwig Institute of Physiology, University of Leipzig, Germany.
Respir Physiol. 1996 Dec;106(3):317-27. doi: 10.1016/s0034-5687(96)00082-5.
We investigated the coordination between breathing and walking in humans to elucidate whether the coordination degree depends more on metabolic load or on breathing or stride frequencies and whether coordination causes energetic economization expressed by reduction of oxygen uptake (VO2). Eighteen healthy volunteers walked on a treadmill at three load levels realized by different velocities and slopes. We analyzed the time intervals between step onset and the onset of inspiration or expiration related to stride duration (relative phase, phi) and computed the relative-phase histogram to assess the degree of coordination. The degree of coordination between breathing and stepping enhanced with increasing walking speed. Increased work load achieved by slope at constant walking speed improved coordination only slightly. No significant VO2 reduction due to coordination was found. VO2 was more strongly related to ventilation variations occurring during coordination. Also the sympathetic tone reflected by the spectral power of heart rate variability was not reduced during coordination. We conclude that during walking the coordination degree increases with increasing stride frequency and that coordination does not necessarily cause energetic economization.
我们研究了人类呼吸与行走之间的协调性，以阐明协调程度是否更多地取决于代谢负荷、呼吸频率或步频，以及协调是否会通过减少摄氧量（VO2）来实现能量节约。18名健康志愿者在跑步机上以三种不同速度和坡度实现的负荷水平行走。我们分析了步幅起始与吸气或呼气起始之间的时间间隔与步幅持续时间的关系（相对相位，phi），并计算了相对相位直方图以评估协调程度。呼吸与步幅之间的协调程度随着步行速度的增加而增强。在恒定步行速度下通过坡度增加工作负荷仅略微改善了协调性。未发现因协调导致VO2显著降低。VO2与协调过程中发生的通气变化更密切相关。协调过程中由心率变异性频谱功率反映的交感神经张力也未降低。我们得出结论，在行走过程中，协调程度随着步频的增加而增加，并且协调不一定会导致能量节约。
