抄録
There are many studies about the relationship between physical activity and health, physical fitness, and chronic disease. The measurement of daily physical activity is important for patients with several major chronic diseases and with physical disabilities, such as coronary heart disease, osteoporosis, and diabetes. In the clinical practice, the assessment of daily physical activity is useful for advising patients about their life style and designing a rehabilitation program to maintain their physical fitness and optimal physical function. Oxygen consumption is the best parameter to show the intensity of different activities; however, it is almost impossible to measure oxygen consumption without inhibiting the subject's daily routine. Many methods instead of measuring oxygen consumption for measurement of physical activity have been studied and reported. The most generally used and well-known methods for this purpose are (a) self-administered quantitative histories or physical activity recall surveys, (b) time study method included in self-report diaries and observation, (c) doubly-labeled water method, and (d) mechanical and electronic monitor. The first two methods have been used many epidemiological studies. However both of these are subjective and influenced by subject inaccuracies or unwillingness to record every activity. The third method involves the administration of isotopes of hydrogen and oxygen and the determination of the washout kinetics of both isotopes as their concentrations fall back down to the pre-administration level. Although the technique is feasible and non-invasive, it has not been widely used because of the cost and scarcity of isotopes. The fourth method can be classified into two types. One type of devices that makes use of biological signals from electromyography (EMG) and electrocardiograph (ECG). The other type of devices that assess the quantity of body movement by using mercury-switch transducer and accelerometer technology. The mechanical and electronic monitors have been improved for overcoming the technical problems in accuracy and confidence by using three-dimensional accelerometer and computer technology. This review demonstrated these methods for measuring physical activity and the recently progress.
