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
What did Siffre do?
He lived in a cave 400ft underground for 2 months in 1962
Describe the conditions Siffre lived in for 2 months?
Complete darkness and in contact with people on the surface every time he ate slept and woke up
What was his sleep wake cycle like whilst he was underground?
24 and a half hours
What do the results from Siffre’s sleep wake cycle suggest?
That we have the same/similar sleep wake cycle independent of light
Describe the sample of Preckel’s study
272 German High School students from 5 different schools
What tests were the high school students given in Preckel’s study?
A owl-lark chronotype questionnaire and standardised cognitive tests
Who was also given a questionnaire about the children’s chronotype?
132 parents
What was found in Preckel’s study?
That being an owl was a significant negative predictor of GPA
In what year did American DJ, Peter Tripp, stay awake for 201 hours and broadcast his radio?
1959
After how many days did he become abusive?
3 days
What happened to Peter Tripp after 5 days?
He began hallucinating spiders in his shoes
After the 201 hours, how long did he sleep for?
24 hours
What did his wife report his behaviour as after he had stayed awake for 201 hours?
She said he had become moody and depressed
People working night shifts should aim for a power nap of what length to reduce fatigue?
20 - 45 minutes
What are power naps essential for?
Maintaining vigilance and alertness
What are some benefits of power naps?
Improved energy, mood, decision making and vigilance
What is melatonin?
A hormone that is released when it’s dark to cause sleepiness
What are melatonin pills particularly useful for?
For sleeping in the day and aligning circadian rhythm with working at night
