“…This is more likely to occur on board a ship because ship OOWs may encounter more difficult and challenging working conditions, as follows [8]: 1) 24/7 working patterns, changing time zones, and shifts (e.g., four-and six-hour shifts [9]), which result in irregular circadian rhythms and working hours, as well as disruption to the biological clock [10,11]. 2) Severe weather, rough seas, seasickness, vibrations, noise, prolonged loneliness, tension, and stress, which result in low sleep quality [12,13]. 3) Frequent port calls and the associated cargo work, excessive workloads, and reduced sleep duration [14].…”