A sedentary lifestyle is prevalent in most industrialised societies. Persuasive evidence allows us to demonstrate that a physically active lifestyle protects against the development and progression of many chronic diseases. The assessment of sedentary individuals for the purpose of exercise testing and or exercise prescription should always culminate in the determination of the relative risk of the individual for traumatic events which may be precipitated by participation in moderate physical activity. Sedentary individuals may be categorised in a low to high risk stratification as apparently healthy (Class I), higher risk (Class II), or known coronary heart disease and/or symptomatic of chronic disease (Class III). An expanded role for allied health professionals, such as a clinical exercise physiologist, may enhance and extend the services of physicians and nurses as they relate to exercise testing, exercise prescription and preventative healthcare in general. Risk stratification will determine the type of exercise test, the exercise prescription and the exercise environment (low to high levels of supervision). The exercise prescription may include a determination of mode, duration, frequency, intensity, and progression of activity. Although target heart rate remains one of the most effective instruments for monitoring exercise intensity, the rate of perceived exertion should be incorporated especially in the titration of exercise prescriptions for those on beta-blockade therapy. Finally the benefits of an exercise programme, derived from a foundation of proper assessment, are numerous and include improvements in cardiovascular fitness, body composition, blood lipid profile and retention of essential muscle mass during the course of the life-cycle. A considerable public health benefit will result if sedentary individuals become regularly more physically active.