Consumer wearable device-based measures of physical activity and energy expenditure in community-dwelling older adults with different levels of frailty: A STROBE compliant study

Physical activity is important for positive health outcomes, and wearable activity devices are useful for tracking physical activity patterns and energy expenditure. This study investigated differences in, and correlations of, duration of physical activity according to activity intensity and energy expenditure among community-dwelling older adults with different levels of frailty. This cross-sectional study enrolled 88 adults older than 65 years from communities between June 2019 and January 2020. The participants were divided into non-frail, pre-frail, and frail groups according to the frailty criteria. Outcomes included the frailty score, duration of physical activity according to the intensity of activity (sedentary, light, fairly active, fairly to very active, and very active), and energy expenditure measured by a consumer wearable device. The duration of physical activity according to the intensity of activity and energy expenditure were compared among non-frail, pre-frail, and frail groups. In addition, linear correlation analysis was used to identify significant associations of objectively measured physical activity and energy expenditure with frailty. Non-frail older adults showed significantly longer daily duration of light to very active physical activity and increased energy expenditure compared to the frail group (P < .05). Additionally, non-frail older adults engaged in significantly more light and fairly to very active physical activity, and showed increased energy expenditure, compared to the pre-frail group (P < .05). The non-frail group showed a significantly lower duration of sedentary behavior compared to the pre-frail group. Correlation analysis showed that frailty was significantly associated with decreased light to very active physical activity and energy expenditure, as well as increased sedentary behavior (P < .05). This study provides evidence of differences in objectively measured physical activity and energy expenditure between frail and non-frail older adults, and reveals an association of frailty with physical activity and energy expenditure. Daily physical activity that exceeds low-intensity, low-energy expenditure activity should be encouraged among older adults with frailty.