Fatigue may be acute or long-term (chronic).
Risk factors associated with both acute and chronic fatigue:
(1) high levels of work stress
(2) high job demands
(3) shorter tour length (a longer voyage would allow for a rest period)
(4) poor sleep quality and/or sleep disturbances
(5) younger age
(6) lack of support
(7) physical hazards
(8) smoking
Additional factors associated with acute fatigue:
(1) switching to port work (longshoreman)
(2) longer shifts, especially if working > 12 hours per day
(3) poor job security
(4) variable shifts
Additional risk factors associated with chronic fatigue:
(1) working in a department other than deck or engineering
The more risk factors that are present, the greater the risk for fatigue. The risk is high if the person has 5 or more risk factors present.