This paper reports the results of a repeat trial assessing the effectiveness of an online theory-based intervention to promote healthy lifestyle behaviours in new university students. The original trial found that the intervention reduced the number of smokers at 6-month follow-up compared with the control condition, but had non-significant effects on the other targeted health behaviours. However, the original trial suffered from low levels of engagement, which the repeat trial sought to rectify. Three weeks before staring university, all incoming undergraduate students at a large university in the UK were sent an email inviting them to participate in the study. After completing a baseline questionnaire, participants were randomly allocated to intervention or control conditions. The intervention consisted of a self-affirmation manipulation, health messages based on the theory of planned behaviour and implementation intention tasks. Participants were followed-up 1 and 6 months after starting university. The primary outcome measures were portions of fruit and vegetables consumed, physical activity levels, units of alcohol consumed and smoking status at 6-month follow-up. The study recruited 2,621 students (intervention n = 1346, control n = 1275), of whom 1495 completed at least one follow-up (intervention n = 696, control n = 799). Intention-to-treat analyses indicated that the intervention had a non-significant effect on the primary outcomes, although the effect of the intervention on fruit and vegetable intake was significant in the per-protocol analyses. Secondary analyses revealed that the intervention had significant effects on having smoked at university (self-report) and on a biochemical marker of alcohol use. Despite successfully increasing levels of engagement, the intervention did not have a significant effect on the primary outcome measures. The relatively weak effects of the intervention, found in both the original and repeat trials, may be due to the focus on multiple versus single health behaviours. Future interventions targeting the health behaviour of new university students should therefore focus on single health behaviours. Current Controlled Trials ISRCTN07407344 .

Several reviews suggest that positive affect is associated with improved longevity, fewer physical symptoms, and biological indicators of good health. It is possible that positive affect could influence these outcomes by promoting healthful cognitions and behaviours. The present review identified conceptual pathways from positive affect to health cognitions and behaviour, and used random effects meta-analysis to quantify the impact of positive affect inductions (versus neutral affect conditions) on these outcomes. Literature searches located 54 independent tests that could be included in the review. Across all studies, the findings revealed no reliable effects on intentions (d₊ = −.12, 95% CI = −.32 to .08, k = 15) or behaviour (d₊ = .15, 95% CI = −.03 to .33, k = 23). There were four reliable effects involving specific cognitions and behaviours, but little clear evidence for generalised benefits or adverse effects of positive emotions on health-related cognitions or actions. Conclusions must be cautious given the paucity of tests available for analysis. The review offers suggestions about research designs that might profitably be deployed in future studies, and calls for additional tests of the impact of discrete positive emotions on health cognitions and behaviour.

Objective: The present research tested whether incidental positive affect promotes pursuit of physical activity goals. Four key features of goal pursuit were examined – setting physical activity goals (Study 1), goal activation (Study 2), and goal prioritization and goal attainment (Study 3). Design: Participants (N_s = 80, 81, and 59, in Studies 1–3, respectively) were randomized to positive affect (joy, hope) or neutral affect (control) conditions in each study. Main Outcome Measures: Questionnaire measures of goal level, goal commitment, and means selection (Study 1); a lexical decision task indexed goal activation (Study 2), a choice task captured goal prioritization and MET minutes quantified goal attainment (Study 3). Results: Study 1 showed that positive affect led to a greater number of intended physical activities, and that joy engendered greater willingness to try activities. In Study 2, a positive affect induction led to heightened activation of the physical activity goal compared to the control condition. The joy induction in Study 3 led to greater physical activity, and a trend towards greater goal prioritization. Conclusion: These findings suggest that positive affect enhances the pursuit of physical activity goals. Implications for health behavior theories and interventions are outlined.