Niinimaa V, Shephard R J
J Gerontol. 1978 May;33(3):362-7. doi: 10.1093/geronj/33.3.362.
CO2 rebreathing measurements of cardiac output have been made in 8 men and 7 women aged 60--76 years, before and immediately after participation in an 11-week endurance training programme. Initial values showed a lower heart rate than in younger subjects at a given percentage of maximum oxygen intake. Stroke volume decreased slightly over the range of 40--80% of maximum oxygen intake. Relative to younger subjects, metabolic needs were thus met to a larger extent by a widening of arterio-venous oxygen difference and redistribution of blood flow. Over the period of observation, training induced a decrease in heart rate and cardiac output at a given sub-maximum work load, with no change in stroke volume or arterio-venous oxygen difference.
对8名年龄在60 - 76岁的男性和7名年龄在60 - 76岁的女性，在参加为期11周的耐力训练计划之前和之后立即进行了通过二氧化碳重呼吸法测量心输出量的操作。初始值显示，在给定的最大摄氧量百分比下，心率低于年轻受试者。在最大摄氧量的40% - 80%范围内，每搏输出量略有下降。因此，相对于年轻受试者，代谢需求在更大程度上是通过动静脉氧差的扩大和血流重新分布来满足的。在观察期内，训练导致在给定的次最大工作负荷下心率和心输出量降低，而每搏输出量或动静脉氧差没有变化。
