AIMS: Most adults with type 2 diabetes mellitus (T2DM) do not engage in sufficient levels of physical activity (PA) to benefit diabetes self-management. Whilst depression is associated with lower levels of self-reported PA, the relationship between depression and motivation for PA has not been examined. Our aims were to examine the associations between depression and different types of PA motivation and to investigate whether PA motivation mediates the relationship between depression and PA behaviour.
METHOD: Data were collected via a national online survey of 458 adults with T2DM: 54% male, (mean±SD) age 62.4±9.90 years, and body mass index (BMI) of 32.18±8.22. Participants completed questionnaires assessing positively worded depressive symptoms (WHO-5), motivation to be active (Behavioral Regulation in Exercise Questionnaire-version 2) and physical activity behaviour (International Physical Activity Questionnaire – Short Form). Regression analyses were conducted, controlling for variables associated with PA behaviour (age, sex, BMI, time since diagnosis, total comorbidities, and insulin use).
RESULTS: Using established cut-off scores, 48% of adults with T2DM reported clinically significant depressive symptoms and 41% were not engaging in sufficient levels of PA. Self-reported depressive symptoms significantly predicted four different types of PA motivation: lower levels of intrinsic motivation (derived from enjoyment of PA), identified motivation (arising from believing that PA will result in valued outcomes), and integrated motivation (reflecting the incorporation of PA into one’s identity); and higher levels of introjected motivation (derived from the desire to avoid feelings of shame or guilt). Importantly, intrinsic, identified, and integrated motivation partially mediated the effect of depression symptoms on PA behaviour.
CONCLUSIONS: Depressive symptoms reduced PA motivation in several important ways, which, in turn, predicted lower levels of PA behaviour. The current findings have important implications for targeting interventions to increase physical activity among older adults with type 2 diabetes.