The COVID-19 pandemic and its lockdown in March 2020 have led to changes in lifestyle and heightened levels of anxiety, depression, and fatigue. This survey examined the factors (affective state, sleep quality, daily activities, mental load, work-related variables) influencing mental and physical fatigue during lockdown and how these relations have evolved one year later. A cohort of 430 workers and 124 retirees were recruited in April-May 2020 (lockdown period, dataset 1), and a subsample (133 workers and 40 retirees) completed the same questionnaire in April-May 2021 (dataset 2). Generalized linear mixed model (GLMM) analyses showed a significant subjective increase in both physical and mental fatigue in both worker and retiree groups during lockdown, and a supplementary increase in physical fatigue and anxiety level at spring 2021 compared to the lockdown period. During lockdown, anxiety level, concerns about COVID-19, work flexibility, mental load, and sleep metrics were associated with the evolution of fatigue among workers. For retirees, only anxiety and physical activity levels were linked to changes in physical fatigue. In April-May 2021, the only associations which remained significant were those in workers between fatigue and anxiety level and workload. These findings suggest that factors accounting for an increased fatigue level during the lockdown seems to be related to the rapid lifestyle adjustments to the sanitary crisis. On the other hand, the increase in fatigue observed one year after the beginning of the pandemic seems to result from more psychological factors associated to the health situation.