All the tired horses in the sun: A person-centered study of morning and evening fatigue trajectories and their association with burnout.

Fluctuations in fatigue over the workweek are a central aspect of the recovery-from-work process that is needed to sustain employee well-being, health, and work functioning. Extant research provides insight into the average fatigue trajectories over a workweek but does not yet address the potential variation in fatigue change patterns that could describe different employee subgroups. This study uses a person-centered approach using latent class growth analysis to explore which fatigue trajectories exist. Specifically, this study draws on 16-day daily diary data from 297 employees to identify existing fatigue trajectories by considering morning and evening fatigue separately. Additionally, it investigates to what extent the identified trajectories may represent manifestations of burnout. The analyses consistently identify three trajectory classes for morning fatigue and evening fatigue that differentially relate to burnout dimensions. The trajectories are characterized by differing fatigue levels across weekdays and by variations in the extent to which recovery occurs over the weekend. These findings highlight the importance of person-centered approaches and differentiating morning and evening fatigue when exploring changes in fatigue over time. Finally, the findings highlight fatigue patterns with limited weekend recovery, which could represent a manifestation of burnout. (PsycInfo Database Record (c) 2025 APA, all rights reserved).