Measuring and positively influencing physical activity and sedentary behaviour in adults with mental illness

Abstract

Background: Mental illness has a high global prevalence, and is associated with higher risk of chronic physical conditions, and reduced psychosocial functioning and life expectancy. Physical activity (PA) protects against chronic disease and mortality risk, and reduces depression and anxiety. Prolonged sedentary behaviour (SB) can have deleterious metabolic consequences, and may be associated with poor mental health.Accurate measurement of PA and SB is important for assessing health risk, and evaluating behaviour change interventions. Objective measures (e.g. accelerometers) allow for unbiased measurement, but do not assess the context of participation, which may be important for intervention planning. Questionnaires can assess context, however, they are prone to reporting errors. The feasibility of using these measures, and the impact of standard data management procedures, has not been assessed in adults with mental illness.PA interventions may positively influence PA levels of adults with mental illness. It is important to understand PA attitudes when designing interventions, as well as the acceptability and efficacy of different exercise approaches. Aims and objectives:The overarching aim of this PhD was to measure, understand, and positively influence the PA patterns of non-institutionalised adults with mental illness. Specific objectives were to: i) assess the utility of questionnaires and accelerometers for measuring PA and SB; ii) investigate questionnaire and accelerometer data management procedures; iii) measure PA and SB levels; iv) assess PA attitudes and opinions; and v) assess the feasibility and acceptability of two exercise protocols. Data from two research studies are presented in six thesis chapters. Study 1Design: Cross-sectional.Method: Participants were adult clients of mental health services. Participants completed self-administered questionnaires on the time spent in PA and SB in different contexts, wore an ActiGraph GT3x+ accelerometer on the hip for 7-days, and rated the ease/difficulty of completing the questionnaires and accelerometry. Participants also completed self-administered questionnaires on PA attitudes and opinions.Results: 142 participants completed the questionnaires (mean age=40yrs, female=43%); of these, 99 (70%) completed the accelerometry (mean age=40yrs, female=47%).ii Participants found it easier to report PA than SB, and to complete accelerometry than questionnaires. Defining a valid day of accelerometry using standard absolute criteria biased the sample by excluding participants with short waking hours; defining a valid day relative to waking hours prevented this bias. The median self-reported time spent in moderate-to-vigorous physical activity (MVPA) and SB was 4.5 hours/week and 10.7 hours/day respectively. Walking for transport, and sitting to watch TV, contributed most to these self-report estimates. The median accelerometer-derived time spent in MVPA and SB was 26 minutes/day and 9.2 hours/day respectively; 7% of MVPA time was in bouts of 10 minutes or ...