This document discusses cardiovascular fitness and flexibility. It outlines the aims of cardiovascular training, including improving efficiency of the heart, lungs, and muscles in oxygen delivery and utilization. It discusses how cardiovascular training can increase VO2 max, decrease resting heart rate and blood pressure, and improve cholesterol and glucose metabolism. The document then covers progression of cardiovascular fitness for general populations and structured programs, including initial conditioning, improvement conditioning, and maintenance phases. It provides recommendations for aerobic exercise duration, intensity, and frequency.