Environmental: Topic Two Flashcards
What is topic two concerning?
Biological rythms
What did Czeisler look into?
Rotating shift schedules that disrupt sleep are improved by applying circadian principles
What was Czeisler’s aim?
To investigate the effects of taking properties of human circadian system in the design of work schedules (specifically the direction of shift rotation)
Describe the sample used in Czeisler’s study
153 male employees working at Great Salt Lake minerals and chemical corporation in Ogden (Utah)
Describe the shift rotation for the 85 rotating shift workers
Working from September to May, they would work on an 8 hour shift for 7 days before rotating to the preceding 8 hour shift (phase advance direction)
What did initial self reports show about the employees on rotating shifts?
That they had more insomnia problems
Give some statistics found from the initial self reports that rotating shift workers had more insomnia problems
29% had fallen asleep at work
90% complained schedules changed too much
81% said it took 2-4 days to adjust each week
What were all workers given?
A presentation and advice on how to adjust sleep patterns
How were the 85 rotating workers divided?
52 (who rotated every 21 days) and 33 (who rotated every 7 days)
In what way did Czeisler change the shift rotation?
Changed the direction from phase advance to phase delay
After how many months were workers given questionnaire’s?
3
After how many months were personnel turnover and plant productivity?
9
How much had complaints dropped by among the 21 day rotation and what did this show about the new shift rotation?
They dropped by 20% as significantly more workers preferred the new phase delay schedules
Which workers appeared to be more satisfied with the shift rotation?
Those on a 21 day rotation were significantly more satisfied
After 9 months, what was the impact on personnel turnover and productivity?
Staff turnover reduced and there was an increase in production
