The COVID-19 pandemic emphasized the importance of physiotherapy for the control and prevention of pulmonary and musculoskeletal complications, with emphasis on the specialty Respiratory Physiotherapy and Physiotherapy in Intensive Care. However, physical, and mental needs due to frontline work, as well as changes in lifestyle in the face of the pandemic, may have interfered with the ability of physiotherapists to work.

To associate the level of physical activity, sleep quality, and demographic and occupational factors with the work ability of physiotherapists on the front lines against COVID-19.

This is an analytical, cross-sectional, and quantitative study, Inclusion Criteria: physiotherapists registered with the Regional Council of Physiotherapy and Occupational Therapy and who signed an TCLE. Exclusion criteria: professionals not registered with CREFITO and who have not signed an TCLE. Brazilian physiotherapists working on the front line against COVID-19 responded to an online keyboard that grouped four instruments: a) demographic, occupational and lifestyle data; b) the International Physical Activity Questionnaire (IPAQ); c) the Pittsburgh Sleep Quality Index (PSQI); d) the Work Ability Index (WAI). Data were analyzed and presented in descriptive statistics (absolute and relative values, mean, standard deviation) and associations between ICT results and independent variables, conferring significance when p ≤ 0.05. The statistical software R version 4.0.0 was used.

Responses were obtained from all regions of Brazil. There was no association between work ability and physical activity level, but work ability was associated with poor sleep quality (p < 0.001) and WAI and PSQI values developed significantly negative (r = - 0.340; p < 0.001). In the adjusted analysis, work ability was associated with female gender (p = 0.018) and with the clinical diagnosis of COVID-19 progress (p < 0.001).

In times of a pandemic, reduced work ability is associated with poor sleep quality, but not with the level of physical activity among physiotherapists on the frontline against COVID-19. The results warn about the potential impact of sleep on the work of professionals who deal with the health of the population, highlighting the need for strategies to support the occupational health of physiotherapists, especially in periods of public health crisis.

the work implies changes for the reorganization of health professionals' work systems to a format that enables assistance without worsening the levels of overload.