Long working hours, poor sleep quality, and work-family conflict: determinant factors of fatigue among Indonesian tugboat crewmembers.

The incidence of fatigue among Indonesian tugboat crewmembers operating on the Mahakam River was considerably high. Working hours, sleep quality, and work-family conflict were strongly associated with fatigue in tugboat crewmembers; therefore, the working hours of tugboat crewmembers need to be improved. Crewmember lifestyle variables need to be studied further.