To stay or not to stay: when mental health becomes the breaking point of nursing sustainability in Portugal

Purpose The sustainability of the nursing workforce in Portugal is increasingly threatened by persistent occupational stress and burnout, which contribute to professional withdrawal and workforce instability. This study examines the influence of occupational stress on nurses’ turnover intentions at three levels – organizational, professional and international – and analyses the mediating role of burnout in these relationships. Design/methodology/approach A quantitative, cross-sectional and correlational research design was employed. Data were collected from 233 nurses working in Portugal using an online questionnaire. Statistical analyses were conducted using IBM SPSS Statistics (v.29) and included descriptive statistics, correlation and multiple regression analyses, exploratory factor analyses for newly developed measures and mediation analysis using Hayes’ PROCESS macro with 5,000 bootstrap resamples. Findings The results revealed high levels of occupational stress and burnout among Portuguese nurses. Work overload and family-related strain emerged as the strongest predictors of perceived occupational stress, whereas career dissatisfaction and strained relationship supervisory where the strongest predictors of burnout. Occupational stress predicted intentions to leave the organization, the profession and the country. Burnout partially mediated the relationship between occupational stress and both organizational and professional turnover intentions, whereas emotional exhaustion fully mediated the relationship between occupational stress and migration intentions. Research limitations/implications The cross-sectional design limits causal inference and the use of snowball sampling may affect the representativeness of the sample. Future research should employ longitudinal designs and broader samples to better capture the dynamic evolution of stress, burnout and withdrawal intentions among healthcare professionals. Practical implications The findings highlight the need for organizational and policy interventions aimed at improving nurses’ psychosocial working conditions, particularly by reducing excessive workload, strengthening supportive leadership and improving career development opportunities. Social implications Addressing stress and burnout among nurses is essential to safeguard the sustainability of healthcare systems. Promoting nurses’ psychological well-being contributes not only to workforce retention but also to the quality and continuity of patient care in increasingly pressured healthcare environments. Originality/value By distinguishing among organizational turnover, professional turnover and migration intentions, this study provides a more comprehensive understanding of the psychosocial mechanisms through which occupational stress contributes to workforce attrition. The findings extend current knowledge on burnout as a mediating mechanism and offer evidence to inform retention strategies that support long-term sustainability of the nursing workforce in healthcare systems.