The human cost of care: the relationship between fatigue and work capacity in Brazilian and Portuguese nursing professionals

Introduction Occupational fatigue among nursing professionals is a multifactorial and complex phenomenon, with significant repercussions for both health and professional performance. In light of this scenario, Work Capacity (WC) emerges as an important indicator of job sustainability, reflecting the balance between individual resources and occupational demands. Objective To analyze the relationship between fatigue levels and work capacity and their associations with sociodemographic, occupational, and health characteristics in nursing professionals from Brazil and Portugal. Methods: This cross-sectional, analytical, and comparative study involved 579 nursing professionals, 370 from Brazil and 209 from Portugal. Sociodemographic, work-related, and health variables were collected, in addition to the application of the Fatigue Assessment Scale (FAS) and the Work Ability Index (WAI). Descriptive and inferential statistical analysis was performed. Results The prevalence of fatigue was high in both countries, reaching approximately 70% of participants, with a higher proportion of severe fatigue in Brazil ( p = 0.030). In the subdomains, Brazilians presented greater mental fatigue, and Portuguese presented greater physical fatigue ( p < 0.05). Work capacity was lower in Portugal ( p < 0.001). A significant inverse correlation was observed between fatigue and WC in both countries ( p < 0.001). Conclusion Fatigue is high in Nursing and shows a consistent inverse relationship with work capacity in different national contexts. There is a clear need for organizational and occupational health interventions aimed at reducing fatigue, improving sleep, mitigating occupational stressors, and promoting job sustainability in nursing.