Physical activity and sedentary behaviour of adults with mental illness

Objectives: To assess physical activity (PA) and sedentary behaviour (SB) in non-institutionalised adults with mental illness, using a combination of self-report and objective measures.

Design: Cross-sectional. 

Methods: Participants completed PA questionnaires (time spent walking for transport, walking for recreation, gardening, vigorous-, and moderate-intensity activities), and SB questionnaires (time spent sitting for TV, travel, work, computer use, and reclining). Participants also wore an accelerometer for 7 days. Accelerometry estimates of time spent in SB, light activity, and moderate-to-vigorous activity (MVPA), bout durations, and, breaks in sedentary time, were calculated. 

Results: 142 participants completed the questionnaires. The median time spent in self-reported MVPA and SB was 4.5 h/week and 10.7 h/day, respectively. Walking for transport, and sitting to watch TV, contributed most to self-report estimates; time spent reclining was an important contributor to SB. Ninety-nine participants completed the accelerometry. The median time spent in accelerometer-derived MVPA and SB was 26 min/day and 9.2 h/day respectively; 7% of MVPA time was in bouts of 10 min or more, and 34% of SB time was in bouts of over 20 min.

Conclusions: A high proportion of participants reported activity levels consistent with physical activity guidelines; however, a small proportion of activity was accumulated in bouts of 10 min or more. Participants also had high levels of SB, about one-third of which was accumulated in bouts over 20 min. PA and SB interventions for this group could target increasing recreational walking, and reducing television time.