Gault Mandy L, Clements Richard E, Willems M E T
Dept. of Sport and Exercise Sciences, University of Chichester, Chichester, UK.
J Aging Phys Act. 2013 Jul;21(3):335-47. doi: 10.1123/japa.21.3.335. Epub 2012 Nov 19.
Cardiovascular responses of older adults to downhill (DTW, -10% incline) and level treadmill walking (0%) at self-selected walking speed (SSWS) were examined. Fifteen participants (age 68 ± 4 yr, height 1.69 ± 0.08 m, body mass 74.7 ± 8.1 kg) completed two 15-min walks at their SSWS (4.6 ± 0.6 km/hr). Cardiovascular responses were estimated using an arterial-volume finger clamp and infrared plethysmography. Oxygen consumption was 25% lower during DTW and associated with lower values for stroke volume (9.9 ml/beat), cardiac output (1.0 L/min), arteriovenous oxygen difference (a-v O2 diff, 2.4 ml/L), and systolic blood pressure (10 mmHg), with no differences in heart rate or diastolic and mean arterial blood pressure. Total peripheral resistance (TPR) was higher (2.11 mmHg) during DTW. During downhill walking, an exercise performed with reduced cardiac strain, endothelial changes, and reduced metabolic demand may be responsible for the different responses in TPR and a-v O2 diff. Future work is warranted on whether downhill walking is suitable for higher risk populations.
研究了老年人在自选步行速度（SSWS）下对下坡（DTW，坡度-10%）和平地跑步机行走（0%）的心血管反应。15名参与者（年龄68±4岁，身高1.69±0.08米，体重74.7±8.1千克）以其SSWS（4.6±0.6千米/小时）完成了两次15分钟的行走。使用动脉容积指夹和红外体积描记法估计心血管反应。下坡行走期间的耗氧量降低了25%，并与较低的每搏输出量（9.9毫升/次搏动）、心输出量（1.0升/分钟）、动静脉氧分压差（a-v O2 diff，2.4毫升/升）和收缩压（10毫米汞柱）相关，心率、舒张压和平均动脉血压无差异。下坡行走期间总外周阻力（TPR）较高（2.11毫米汞柱）。在下坡行走期间，一种心脏应变降低、内皮变化和代谢需求降低的运动可能是TPR和a-v O2 diff产生不同反应的原因。关于下坡行走是否适合高危人群，未来有必要开展相关研究。
