IL SONNO NEL LAVORO A TURNI: CONFRONTO TRA TURNI "3X8" E "2X12".

Abstract: Sleep in night shift work: comparison between “3x8” and “2x12” fast rotating shift schedules The study was aimed at assessing the impact of 3 types of fast rotating shift systems on stress, fatigue, sleep and hormonal secretion. Subjects: Among 294 hospital nurses, examined in a survey on work related stress, three groups of 10 nurses were randomly selected for a comparison of three shift work schedules: a) 10 working in the resuscitation unit on a “3x8” shift system in a 5-day cycle with a “quick return”: Afternoon (14-21); Morning (07-14) and Night (21-07); End of Night shift; 2 Rest days; b) 10 working in the surgical ward on a “3x8” shift system in a 6-day cycle with a “quick return”: Afternoon; Morning; Morning and Night; End of Night shift; 2 Rest days; c) 10 working in the delivery room on a “2x12” shift system in a 5-day cycle: Daywork (07-19); Nightwork (19-07); End of Night shift; 2 Rest days. Seventeen nurses were women and 13 men, aged between 23 and 46 years (mean 34.3) and with work seniority between 1.4 and 28 years (mean 11.4). All were in good health and not taking any medication. Methods: They have been submitted to a semi-structured interview including the Standard Shiftwork Index, the Job Demand-Control and the Effort Reward Imbalance questionnaires, the Epworth sleep scale. During the whole shift cycle, the nurses recorded their activity and rest periods by actigraphy and personal diaries, assessing sleepiness by the Karolinska Sleepiness Scale and quality of sleep by a 10-point visual scale. They also took saliva samples at 0700 and 2300 of each working and rest day for dosage of cortisol, cortisone and melatonin. Results: The nurses reported more sleep troubles in both “3x8” than in “2x12” shift schedule. According to actigraphy, in both “3x8” shift schedules the duration of night sleep between afternoon and morning shifts is reduced by 35% as compared to rest days, and sleep between morning and night shifts in the same day lasts less than 3 hours on average, showing a significantly higher fragmentation in both occasions. Also subjective sleepiness is significantly higher before night shift in both “3x8” shift schedules than in the “2x12” one. In the surgery ward, where they can nap/sleep up to 3 hours during the night shift, the nurses have a 40% shorter sleep in the morning after. In the “2x12” shift schedule the night sleep duration between Day and Night shift is the same as in the rest days. As far as hormonal secretion, cortisol and cortisone did not change significantly their normal circadian phase in all the three shift schedules, whereas melatonin showed a more irregular pattern.