Env=> biological rhythms

Question 1

Key research=> Czeisler et al

Rotating shift work schedules that disturb sleep are improved by applying circadian principles

Answer 1

Phase delay= delaying bedtime (staying up later)
Phase advance= advancing bedtime (going to bed earlier)

How often should people change shifts?
Which direction should they change shifts?

Male employers=> Potash production facticity in Utah USA

• Group 1= ROTATING SHIFTS (sometimes day/sometimes night) 85
• Group 2= FIXED SHIFTS (only day/night shifts)

-Self-reports= employers on rating shifts= more problems with insomnia than those on non-rotating shifts + 30% reporting they fell as deep at work at least once PHASE ADVANCING

Divided 85 of rotating shift workers into 2 groups=> PHASE DELAY

• Rotating every 7 days
• Rotating every 21 days

After 3 months= questionnaires

• Significantly more workers preferred new phase delay shifts
• Complaints that schedule changed too often dropped by 20% for workers on 21 days rotation + were significantly more satisfied with schedule compared to 7 day relation + significantly increased scores on health index

After 9 months=
-Increased rates of potash harvesting + production

Question 2

Siffre=> living underground

Answer 2

Lived 400 feet below ground in a cave= French - Italian Alps

• 2 months
• Entirely dark apart from light bulb
• Body followed a daily sleep-wake cycle

However it was 24 hrs + 30 mins stead of 24 hrs

Humans have internal body clock which is independent of night + day

Question 3

Preckel et al=> German high schools

Answer 3

• People either have morning chronotypes (sleep before 11 + awake by 8)= larks
• Evening types (sleep after 11 + awake after 8)= owls
• 272 students in 9th + 10th grade at 5 German schools
• Given chronotype questionnaire + standardised cognitive test in class
• 132 parents filled out a questionnaire at home
• Being an owl had negative impacts of overall grade point average= schools suit larks more

Question 4

Peter Tripp=> radio broadcast

Answer 4

Raise money for charity= broadcast his radio show non-stop
-201 hours total

The effects=

• Abusive 3 days into it
• Hallucinating= thought his shoes were full of spiders- 5 days. They were in sync with them he should have been sleeping (dreaming)
• Body temp was very low

After= deep sleep for 24 hrs. Became moody + depressed Relationship with wife become bad + got divorced

Question 5

Overcoming effects of shift work/jet lag

Answer 5

Power naps=
Royal College of Physicians
-Recommended that junior doctors working night shifts should take short restorative power naps (20-45 mins)
-Reduces the risk of fatigue
-Study in Canada=> 10 out of 13 nurses who regularly napped=> benefits=> improved energy, mood + decision making

Melatonin pills=
Hormone produced by body=> apart of circadian rhythm
When it’s dark=> high levels released
-Can be brought in pills=> help sleep during hay + align circadian rhythm