School of Social Welfare, University of California, Berkeley, CA, USA.
Department of Statistical Sciences, Sapienza University of Rome, Rome, Italy.
Ann Behav Med. 2022 Feb 11;56(2):212-218. doi: 10.1093/abm/kaab028.
Low physical activity is an important risk factor for common physical and mental disorders. Physical activity interventions delivered via smartphones can help users maintain and increase physical activity, but outcomes have been mixed.
Here we assessed the effects of sending daily motivational and feedback text messages in a microrandomized clinical trial on changes in physical activity from one day to the next in a student population.
We included 93 participants who used a physical activity app, "DIAMANTE" for a period of 6 weeks. Every day, their phone pedometer passively tracked participants' steps. They were microrandomized to receive different types of motivational messages, based on a cognitive-behavioral framework, and feedback on their steps. We used generalized estimation equation models to test the effectiveness of feedback and motivational messages on changes in steps from one day to the next.
Sending any versus no text message initially resulted in an increase in daily steps (729 steps, p = .012), but this effect decreased over time. A multivariate analysis evaluating each text message category separately showed that the initial positive effect was driven by the motivational messages though the effect was small and trend-wise significant (717 steps; p = .083), but not the feedback messages (-276 steps, p = .4).
Sending motivational physical activity text messages based on a cognitive-behavioral framework may have a positive effect on increasing steps, but this decreases with time. Further work is needed to examine using personalization and contextualization to improve the efficacy of text-messaging interventions on physical activity outcomes.
CLINICALTRIALS.GOV IDENTIFIER: NCT04440553.
低身体活动是常见身心障碍的一个重要风险因素。通过智能手机提供的身体活动干预措施可以帮助使用者保持和增加身体活动量，但结果参差不齐。
本研究在一项学生人群的微随机临床试验中，评估了每天发送激励和反馈短信对次日身体活动变化的影响。
我们纳入了 93 名参与者，他们在 6 周的时间内使用身体活动应用程序“DIAMANTE”。每天，他们的手机计步器被动地跟踪参与者的步数。他们根据认知行为框架被微随机分配到接受不同类型的激励信息和关于他们步数的反馈。我们使用广义估计方程模型来测试反馈和激励信息对次日步数变化的有效性。
与不发送短信相比，发送任何短信最初会导致每日步数增加（729 步，p =.012），但这种效果随着时间的推移而减弱。一项单独评估每个短信类别的多变量分析显示，初始的积极效果是由激励信息驱动的，尽管效果较小且呈趋势显著（717 步，p =.083），但不是反馈信息（-276 步，p =.4）。
基于认知行为框架发送激励性身体活动短信可能对增加步数有积极影响，但这种影响随着时间的推移而减弱。需要进一步研究如何使用个性化和情境化来提高短信干预对身体活动结果的效果。
临床试验.gov 标识符：NCT04440553。
