Mental imagery-based self-regulation: Effects on physical activity behaviour and its cognitive and affective precursors over time.

Abstract

OBJECTIVES\n(1) Test whether a mental imagery-based self-regulation intervention increases physical activity behaviour over 90\xa0days; (2) Examine cognitive and affective precursors of change in physical activity behaviour.\n\n\nDESIGN\nA randomized control trial with participants (N\xa0=\xa0500) randomized to one of six intervention conditions in a 3 (risk communication format: bulleted list, table, risk ladder) x 2 (mental imagery behaviour: physical activity, active control [sleep hygiene]) factorial design.\n\n\nMETHODS\nAfter receiving personalized risk estimates via a website on a smartphone, participants listened to an audiorecording that guided them through a mental imagery activity related to improving physical activity (intervention group) or sleep hygiene behaviour (active control). Participants received text message reminders to complete the imagery for 3\xa0weeks post-intervention, 4 weekly text surveys to assess behaviour and its cognitive and affective precursors, and a mailed survey 90\xa0days post-baseline.\n\n\nRESULTS\nPhysical activity increased over 90\xa0days by 19.5 more minutes per week (95%CI: 2.0, 37.1) in the physical activity than the active control condition. This effect was driven by participants in the risk ladder condition, who exercised 54.8 more minutes (95%CI 15.6, 94.0) in the physical activity condition than participants in the active control sleep hygiene group. Goal planning positively predicted physical activity behaviour (b\xa0=\xa012.2\xa0minutes per week, p\xa0=\xa00.002), but self-efficacy, image clarity, and affective attitudes towards behaviours did not (p\xa0>\xa00.05).\n\n\nCONCLUSIONS\nMental imagery-based self-regulation interventions can increase physical activity behaviour, particularly when supported by personalized disease risk information presented in an easy-to-understand format.