An optimal exercise prescription is a balance between the frequency, intensity, duration, and mode of exercise. Heart rate is a useful indicator of the intensity of effort and body's physiological adaptation. Heart rate monitoring is an important component especially in cardiovascular fitness assessment and training programmes. Polar heart rate monitors have been developed to measure healthy people’s heart rate and they target to help people exercise safely and effectively.
The intensity of physical exercise should always be based on a persons' fitness level and the goals of the exercise e.g. maintain or improve health/fitness/performance and help in weight management.