Exercise

The concept of exercise encompasses an expansive list of possible activities. In general, exercise may be defined as purposeful physical exertion that significantly increases the activity level in key physiologic systems (i.e., cardiovascular, pulmonary, and skeletal muscle). Exercise is quantified and prescribed by four key parameters: frequency, intensity, time, and type of activity. Although the term exercise is commonly the preferred descriptor of a structured training program (e.g., aerobic or resistance training), any physical exertion that causes a meaningful increase in physiologic activity of the aforementioned systems for a sustained period of time may be considered exercise. In this context, an infant who is crawling and an 85-year-old who is taking a walk in the park are both partaking in exercise. Exercise, or sustained physical ...