Increasing physical activity and effectively managing stress can positively impact immunity and may reduce the duration of respiratory tract infections (RTIs). As part of a larger trial, participants accessed a digital behavioural change intervention that encouraged physical activity and stress management to reduce RTIs. We aimed to understand the barriers and facilitators to engaging in physical activity and stress reduction.

A qualitative process analysis from semistructured interviews of the behavioural intervention in a randomised control trial.

Primary care in the UK.

34 participants (aged 18–82 years) in the behavioural intervention arm.

The larger trial involved four interventions: a gel-based antiviral nasal spray; a saline water-based nasal spray; a behavioural intervention; usual care. In this study, we focused on participants allocated to the behavioural intervention. The behavioural intervention included two components: one to increase physical activity (getting active) and another for stress management techniques (healthy paths) to reduce RTIs.

We analysed the interviews using thematic analysis with a critical realist perspective (focusing on). We developed five themes: digital intervention engagement, views on intervention allocation, the role of getting active, the role of healthy paths and benefits reinforcing behaviour. Participants’ views on the relevance and benefit of the behavioural intervention shaped their engagement with the intervention website and behaviour. Facilitators of intervention engagement included awareness of inactivity, goal setting, increasing immunity, positive outcome expectations and benefits from changing behaviour. Barriers to engagement included negative outcome expectations, such as around efficacy of the behaviours.

Overall, the results highlighted the importance of positive expectations for a digital intervention promoting physical activity and stress management for RTI reduction. Future interventions should consider how to clearly communicate a broad range of perceived benefits to users.

The trial was prospectively registered with International Standard Randomized Controlled Trial Number (ISRCTN) registry (17936080).