Efficacy of a randomized controlled self-regulation based physical activity intervention for chronic fatigue: Mediation effects of physical activity progress and self-regulation skills

Objective: Examine the medium-term effects of a brief physical activity (PA) self-regulation (SR) based intervention (4-STEPS program) for chronic fatigue, and explore the mediating effects of PA related variables and SR skills. Methods: A two-arm randomized controlled trial (Usual Care vs 4-STEPS) was carried out The 4-STEPS program consisted of Motivational Interviewing and SR-skills training. Fatigue severity (primary outcome) and impact, PA, health-related quality of life (HrQoL), and somatic and psychological distress were assessed at baseline, posttreatment (12 weeks) and 12 months follow-up. Results: Ninety-one patients (45 intervention and 46 controls) were included. At follow-up, there were significant treatment effects on fatigue severity (g = 0.72) and fatigue impact, leisure-time PA, and physical and psychological HrQoL. No significant effects were found for number of daily steps and somatic and psychological distress. Fatigue severity at follow-up was partially mediated by post-treatment progress on a personal PA goal (effect ratio = 18%). Conclusion: Results suggest that a brief intervention, focusing on the formulation and pursuit of personal PA goals and the use of SR skills, produces sustained benefits for fatigue severity. Despite these promising results, dropout was high and the intervention was not beneficial for all secondary outcomes.(C) 2016 Elsevier Inc. All rights reserved.