Final answer:
In cardiorespiratory development, intensity is prescribed relative to heart rate, guiding exertion levels to meet fitness goals.
Step-by-step explanation:
Intensity in cardiorespiratory development is most commonly prescribed relative to heart rate. This relation is crucial because the heart rate helps determine the level of exertion during cardiorespiratory exercise and allows for the adjustment of workout intensity to achieve desired fitness results. Cardiorespiratory endurance exercises and how to modify their intensity can be organized in various ways, such as low intensity or skill-based activities, moderate exercise programs, or endurance programs, which may involve moderate to high-intensity exercise for more extended periods.