Abstract With the growing popularity of mobile health (mHealth) devices, including smartphones and wearable devices, information and communications technology has gained high importance in healthcare settings. This study aimed to summarize the current trends in physical activity research wherein mHealth devices are used and provide perspectives for future research. Until recently, questionnaire surveys were primarily used to evaluate physical activity. While questionnaire surveys are effective for subjective evaluation, the use of mHealth devices enables large-scale, real-time, objective evaluation of physical activity. In addition, mHealth devices automatically collect and aggregate data. This allows researchers to perform retrospective analysis of a wide range of indicators of physical activity and health. Particularly, the use of smartphones is highly likely to contribute to large-scale monitoring and health interventions because of their ubiquity. Even though there are fewer users of wearable devices (wrist-worn devices) than those of smartphones, using wearable devices allows for the evaluation of 24-hour movement patterns. The use of wearable devices helps perform further precise analysis that focuses not only on the total amount of physical activity but also on the quality, including measures of intensity, duration, frequency, type, and time. Moreover, some wrist-worn devices measure physiological information such as heart rate and may also provide location information. Combining such data with information from an accelerometer associated with a device may allow for further specific and detailed evaluation of physical activity. The validity of physical activity assessment using major mHealth devices has been confirmed in several studies and is comparable to that of pedometers and accelerometers developed for research purposes. Evaluation of physical activity using mHealth devices involves issues related to the representativeness of the target population and continuity of data, as well as the need for ethical considerations based on privacy policies. While mHealth devices may be used by individuals as a health management tool, it is also expected that the evaluation of physical activity using mHealth devices will be performed in various settings such as epidemiological and clinical studies on physical activity, as well as community services wherein indicators of physical activity are used.
Keywords: eHealth; exercise; mobile health; population health; smart health; wearable technology.