On the move for the sake of science, subjects in a Yale University fitness study are measured against each other. Thirty-seven-year-old Rich (left) and 60-year-old Larry (center), both of whom exercise regularly, are neck and neck in cardiovascular fitness. By comparison, 35-year-old Salvatore (right) leads a sedentary life that negatively affects his cardiovascular and respiratory fitness. His heart and major arteries are visibly smaller, and his VO2max—the amount of oxygen his body is able to use—is lower. The brighter colors in his leg show that his muscles had to work harder to complete an hour on the treadmill. The point? Our bodies are programmed to exercise.

我们的身体会为运动做适应性改变！耶鲁大学做的研究。上图左为37岁的Rich，图中为60岁的Larry，二者都有固定的心肺适能的运动。而图右为35岁的Salvatore ，久坐、看电视、看书、上网、吃零食等，没有规律运动的生活作息(Sedentary lifestyle)，他的心脏和主要血管小，他的VO2max（身体利用氧气的数量）低。三人同时在跑步机上跑一小时，颜色愈亮的部位代表肌肉愈吃力的部份。

所谓心肺适能，是指个人的肺与心脏，从空气中携带氧气并将氧气输送到组织细胞加以使用的能力。因此心肺适能可以说是个人的心脏、肺、血管与组织细胞的有氧能力指标。心肺适能较佳，可以使我们运动持续较久、且不致于很快疲倦，也可以使我们平日工作时间更久，更有效率。心肺适能较差，不仅容易疲劳、精神萎靡不振，而且较容易有心血管疾病的发生。主要测量指标Vo2max.

运动性适应性改变影响深远！而心肺适能的运动方式包括快走、慢路、有氧、跳绳、游泳、骑脚踏车等，心肺适能可以说是身体活动的基础，反应在你的精神状态。改善心肺适能带给你的益处，包括活的更久、情绪会比较愉悦、拥有较好的身型、自信、运动的肌耐力及心跳率会更好。