Text-messaging intervention to improve physical activity and sedentary behaviour in adolescents

Adolescence presents a crucial time to establish healthy lifestyle behaviours such as sufficient levels of physical activity (PA) and reduced sedentary behaviour (SB), considering their positive impact on health in later life. Technology-based interventions have been identified as a potentially promising approach for supporting successful health behaviour change with a recent systematic review reporting that text messages can be an effective tool for improving PA and SB in youth. However, evidence surrounding the feasibility and effectiveness of programs involving text messages without the addition of other components such as educational sessions is scarce. The present study therefore aimed to assess the following: 1) the feasibility of delivering a text-messaging intervention targeting PA and SB, 2) the effectiveness of the intervention in improving PA and SB, 3) participant preferences and experience of the intervention. Following institutional ethics approval, 2 classes (N=52) from a local secondary school agreed to receive text messages via the NHS’s Florence text-messaging system for 3 weeks. Cluster randomisation resulted in a class of twenty-five participants (mean age 17.08 years) being allocated to the intervention group, with the second class of twenty-seven pupils (mean age 15.07 years) representing the waitlist control group. The text messages were informed by Theory of Planned Behaviour and Social Cognitive Theory. To assess feasibility, study procedures and recruitment and retention of participants were assessed. Wrist-worn ActiGraph GT3X+ devices were used to measure PA, with ActivPAL 4 monitors worn on the thigh used to determine SB. Post-intervention, twenty-four participants of the intervention group took part in focus group discussions to explore preferences and experiences of the intervention. Initial analysis of focus group data shows no consensus with regards to preference of a specific type of text message, such as those describing benefits of PA or offering instructions of how to increase PA. It appears timing of text messages had an impact on behaviour change with messages sent during school hours being perceived as less useful. Participants mentioned the messages to be encouraging and increasing their knowledge and awareness of the benefits of PA. However not all participants felt the messages resulted in them increasing PA or reducing SB. Focus group analysis is ongoing as is the analysis of the feasibility and activity data collected. The present study will provide crucial evidence to inform the development and evaluation of more effective behaviour change interventions promoting healthy lifestyles in youth.