Work hours, sleep patterns and fatigue among merchant marine personnel

Abstract

SUMMARY A field study ofwork and sleep patterns among commercial merchant marine personnel is reported. Data collected over a 10-30-d period from 141 subjects aboard eight ships included information concerning work-rest schedules, sleep timing, alertness on the job and critical fatigue. The data indicate that watchstanders on the 4-on, 8-off schedule show considerable disruption in their sleep. The average sleep duration for all mariners is 6.6 h; watchstanders obtain their sleep in fragmented periods that are frequently less than 5 h in duration. Analysis of critical fatigue shows an incidence of 1 --240/0 across personnel and measures. Of particular concern are the watchstanders on the 04.00-08.00 schedule, who sleep less than 4 h per 24-h period 22% of the time.Potential countermeasures, including changes in scheduling and staffing are proposed.

A systematic review of the sleep, sleepiness, and performance implications of limited wake shift work schedules

“…Analysis of variance (ANOVA) with simple posthoc comparisons was then conducted to assess differences between rosters and between crews within rosters. In this analysis, it is acknowledged that sleep measures differed between studies, with two studies using PSG (29,39), four studies using actigraphy (22,26,30,36) and the remaining studies using sleep diaries (17,28,32,33,44).…”

“…Second, sleep duration was related to the quality of LWSW sleep environment (eg, ship cabins, submarine bunks, mining "dongas" and train sleeping wagons). Underlying the importance of environmental factors for optimizing sleep, most studies reported that sleep length was shorter on operations compared to either home or layover (22,25,29,32,36,45). In their large (N=362) survey of offshore fleet workers, Hansen et al (34) found the most frequently endorsed problems when sleeping at sea were noise (55%), cabin vibration (34%), cabin temperature/humidity (30%), alarms (29%), and poor bedding (21%), all of which were more highly ranked than "bothered by shift work" (18%).…”

“…Nine studies reported sleepiness measures, and of these, two reported visual analog scale (VAS) alertness (27,32), five reported Karolinksa Sleepiness Scale (KSS) (17,23,30,33,39) and the others employed author-generated measures of sleepiness/alertness. Therefore, harvesting of performance or sleepiness/alertness measures from studies to compile for meta-analysis was deemed unfeasible and not pursued.…”

“…Eight of the studies identified in this review used a within-subject's design (18,22,23,25,29,(36)(37)(38), ten a between-subject's design (17,24,26,27,30,31,34,35,39,40), and four employed a mixed within-and between-subjects design (19,28,32,33). Seventeen studies were field-based (17-19, 22, 24-32, 34-37) and five used laboratory simulations (23,33,(38)(39)(40).…”

“…Only primary, peer-reviewed articles published in English were included, while studies examining pharmacological interventions were excluded. From this search, we identified 22 papers which examined LWSW (17)(18)(19)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), two pairs of which overlap (25,29,36,37), leaving a total of 20 independent studies. The identified studies are summarized in table 1.…”