The Impact of Fragmented Physical Activity on Physical Function in European Older Adults in the SITLESS Study

Patterns of physical activity (PA) may be associated with physical function independently of total volume. The study aim was to explore associations of PA fragmentation (PAF) and function in ≥65-year-old European adults (SITLESS study: n=1360). The ActiGraph wGT3X+ accelerometer was worn for seven consecutive days at the dominant hip. PAF was assessed as the ratio of the number of ≥10-second PA bouts divided by an individual’s total minutes in PA. Physical function was assessed using the 2-minute maximum walk test (2MWT) and short physical performance battery test (SPPB). Multiple linear regression was utilized adjusting for relevant covariates. Lower PA fragmentation was significantly (p<0.01) associated with longer 2MWT distances and better SPPB scores. The model explained 54% and 41% of the variance in the 2MWT distance and in SPPB score, respectively. Increased PAF seems associated with reduced physical function; independent of sedentary behavior and numerous important health and socio-demographic covariates.