Resumen:
BACKGROUND: Burnout syndrome, a consequence of chronic workplace stress, poses a critical challenge for health workforce sustainability. Junior doctors in postgraduate training represent a strategic cohort of the health workforce, as they face multiple stressors, including extended working hours, emotional overload, and escalating responsibilities that compromise well-being and performance. Despite its relevance for workforce planning and retention, this population remains insufficiently studied. This study aims to estimate burnout prevalence among junior doctors in Spain and analyse associated factors with implications for human resources management. METHODS: A cross-sectional nationwide survey was conducted among Spanish physicians who began their training between 2015 and 2024. Burnout was assessed using the Maslach Burnout Inventory-Human Services Survey (MBI-HSS). Additional variables included sociodemographic data, perceived quality of life, psychosocial impact and coping mechanisms. RESULTS: A total of 1,419 valid responses were obtained, covering all Autonomous Communities. Participants' mean age was 31.4 years; 72% were women, and 93.7% worked in public healthcare. Burnout prevalence was high: 93.9% met criteria for at least one affected dimension, 81.4% for two, and 50.9% for all three. Burnout was significantly associated with female gender, on-call duties, and various psychosocial factors such as sleep disturbances, reduced sexual desire, lower perceived quality of life, and increased psychotropic use. CONCLUSIONS: The extremely high prevalence of burnout among junior doctors in Spain signals a systemic risk for workforce stability and quality of care. These findings underscore the need for policy interventions to optimise working conditions, regulate workloads, and integrate mental health support within human resources strategies. Addressing burnout is essential to strengthen health workforce resilience and ensure sustainable health system performance.