Subjective and Objective Evaluation of Sleep and Performance in Daytime Versus Nighttime Sleep in Extended-Hours Shift-Workers at an Underground Mine

Abstract

Extended hours of shift work has the potential for adverse consequences for workers, particularly during the nightshift, such as poorer sleep quality during the day, increased worker fatigue, and fatigue-related accidents and decreased work performance. This study examined subjective and objective measurements of sleep and performance in a group of underground miners before and after the change from a backward-rotating 8-hour to a forward-rotating 10-hour shift schedule. The purpose of this study was to evaluate the short- and long-term impact of a shift schedule change on sleep and performance. The results demonstrated improved subjective and objective measures of sleep and performance on the new 10-hour nightshift schedule. The 10-hour nightshift workers subjectively reported more refreshing sleep, fewer performance impairments and driving difficulties than 8-hour nightshift workers. The results of the objective measures of sleep and performance on the 10-hour nightshifts were overall similar or possibly better than those measured on the 10-hour dayshifts. These are some of the first data to suggest that a nightshift that does not encompass the entire night period could have significant benefits to shift-workers. We suggest that these benefits are mostly the result of the timing of the new nightshift start and end times rather than other shift-schedule factors.

Investigation of task performance variations according to task requirements and alertness across the 24-h day in shift workers

“…On the one hand, task performance decrements in early morning hours have been observed for reaction time. This finding is also in agreement with a number of studies performed under controlled conditions in the laboratory (Monk et al, 1985;Monk & Carrier, 1997;Casagrande et al, 1997;Heuer et al, 1998;Owens et al, 2000;Gennaro et al, 2001;Wright et al, 2002), in simulated shift-work conditions (Fröberg et al, 1975;Colquhoun et al, 1968;Johnson et al, 1992), and in real shift-work settings (Tilley et al, 1982;Hossain et al, 2004). On the other hand, in the more demanding cognitive tasks, time-of-day effects interacted with the task components that were manipulated.…”

“…They reported reduced performance on the night-shift for reaction time, mental arithmetic, and search performance (Tilley, Wilkinson, Warren, Watson, & Drud, 1982;Hossain, Reinish, Heslegrave, Hall, Kayumov, et al, 2004; Wojtczak-Jaroszova, Makowska, Rzepecki, Banaszkiewicz, and Romejko, 1978). However, performance changes have not systematically been reported in field studies, for instance for serial reaction time, digit symbol substitution, and manual tracking (Costa, Gaffuri, Perfranceschi, Tansella, 1979;Lowden, Kecklund, Axelsson, & Akerstedt, 1998).…”

Health-related interventions among night shift workers: a critical review of the literature

“…Fifteen interventions evaluated a change in shift schedule (39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54) (table 4). Mean study quality was 14.9 (range: 9-20).…”

“…Mean study quality was 14.9 (range: 9-20). Interventions involved changes from a backward (counter-clockwise) to forward (clockwise) rotating shift (N=6) (40-42, 45, 48, 49, 53) and vice versa (N=1) (44), switching from 8-to 10-or 12-hour shifts (N=6) (43,46,47,50,51,54), adjusting the shift schedule based on ergonomic principles (39), flexible shift scheduling (53), and delaying shift start time (52). Many changes from backward to forward rotating shifts also increased rotation speed (N=4) (40,42,45,53).…”

Efeito da inversão dos turnos de trabalho sobre capacidade aeróbia e respostas cardiovasculares ao esforço máximo

“…Podemos justificar nossos achados não pela variação circadiana dos níveis de consumo máximo de oxigênio e sim, pelo prejuízo à performance que a privação do sono causa aos indivíduos que possuem turnos de trabalho invertidos. Hossain et al (2004) (22) , estudando a qualidade do sono, atenção e performance das atividades realizadas por mineradores que trabalhavam em turno diurno e noturno, relataram em redução na atenção e desempenho daqueles com sono vigília invertido, onde o fator fadiga foi primordial para esta queda na habilidade e capacidade mental e motora.…”