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Sleepiness in various shift combinations of irregular shift systems
Mikael Sallinen1, Mikko Härmä, Pertti Mutanen
1Brain Research Unit, Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, 00250 Helsinki, Finland.
Industrial Health
|March 1, 2005
Summary
Severe sleepiness affects many shift workers, particularly those on night shifts. Factors like shift length, start time, and individual sleep needs significantly impact sleepiness risk.
Area of Science:
- Occupational Health
- Sleep Science
- Transportation Safety
Background:
- Shift work is prevalent in transportation industries, impacting worker alertness.
- Understanding sleepiness triggers is crucial for preventing accidents.
Purpose of the Study:
- To investigate the occurrence and risk factors of sleepiness in train drivers and traffic controllers working various shift patterns.
- To analyze the relationship between shift combinations, sleep patterns, and individual characteristics with workplace sleepiness.
Main Methods:
- Utilized three weeks of sleep/work shift diary data from 230 transportation workers.
- Employed a generalized linear model with repeated measurements to analyze sleepiness occurrence (Karolinska Sleepiness Scale ≥ 7).
- Included explanatory factors: shift types, sleep duration, and individual characteristics.
Main Results:
- Prevalence of severe sleepiness ranged from 25-62% for night shifts and 12-27% for morning shifts.
- Sleepiness occurrence did not systematically vary between specific shift combinations.
- Increased sleepiness risk linked to high sleep need, long shifts (night), and early starts/short sleep (morning). Having a child also increased night shift sleepiness risk.
Conclusions:
- Shift history (24-36h prior) showed weak association with sleepiness.
- Shift length, start time, and individual sleep need are key factors influencing sleepiness risk.
- Findings highlight the need for targeted interventions to mitigate sleepiness in shift workers.
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