1. Copyright Catherine M. Burns 1 Circadian Rhythms and Shiftwork Text Chapter 13 p. 343-348

2. Copyright Catherine M. Burns2 Sleep Loss  Have you ever pulled an “all-nighter”?  Flown the “red-eye” flight?  How did you feel afterwards?

3. Copyright Catherine M. Burns 3 Who is sleep deprived right now?

4. Copyright Catherine M. Burns4 The Epworth Sleepiness Scale  A standardized scale used by sleep experts  Assess your chance of dozing 0 would never dose 1 slight chance of dozing 2 moderate chance of dozing 3 high chance of dozing  Scale: National Sleep Foundation

5. Copyright Catherine M. Burns5  Sitting and reading?  Watching television?  Sitting still in a public place (theatre or movie)?  Passenger in a car for an hour?  Lying down in the afternoon?  Sitting and talking to someone?  Sitting quietly after lunch?  In a car while stopped in traffic?

6. Copyright Catherine M. Burns6 Causes of Sleep Loss  deliberately staying awake  sleeping at unnatural times during daylight counter to one’s circadian rhythms  sleeping with the effects of caffeine or alcohol

7. Copyright Catherine M. Burns7 Circadian Rhythms  natural physiological cycle the body goes through every day  temperature, metabolism, and chemical level changes  low temperature in the morning rises during the day then drops (6:30-6:30 roughly)  slightly longer than 24 hours  People with circadian rhythm disorders

8. Copyright Catherine M. Burns8 Body Temperature 6am6pm 36.5 37.0 Text p. 345 Figure 13.5

9. Copyright Catherine M. Burns9 Circadian Rhythms  Cycle correlates with sleepiness sleep efficiency (how long we sleep) performance  Strong correlation with errors and accidents

10. Copyright Catherine M. Burns10 Performance 6am6pm6am6pm6am6pm6am6pm Psychomotor Performance Symbol cancellation Reaction Time Digit summation Text Figure 13.6 p 346

11. Copyright Catherine M. Burns11 Circadian Rhythms and Driving  When would you expect more accidents? With the spring time change? With the fall time change? Why?

12. Copyright Catherine M. Burns12 Accidents in Canada 1991-1992 Spring Fall Day of the change Day before, of, after the change Source: Sleep thieves

13. Copyright Catherine M. Burns13 Accidents in Israel # of accidents Time 4am4pm Source: Sleep thieves, Stanley Coren

14. Copyright Catherine M. Burns14 Circadian Rhythms and Driving

15. Copyright Catherine M. Burns15 Circ Rhythms and Accidents  Which of the cases we’ve studied could have been influenced by circadian rhythms?

16. Copyright Catherine M. Burns16 Effects of Sleep Disruption  impaired judgement  reduced ability to learn  reduced ability to store new material  inability to plan

17. Copyright Catherine M. Burns17 Assessing Sleep Debt  Do you need an alarm clock to wake up?  Do you hit the snooze to get a few more minutes?  Getting out of bed is a struggle  Sleeping through the alarm  Sleeping longer on weekends than during the week  Getting sleepy sitting and reading  Dozing off when watching TV?  Feeling dozy after lunch  Drink more than four cups of coffee or tea?

18. Copyright Catherine M. Burns18 Solutions  get more sleep!  some sleep is better than no sleep  napping (even 15 minutes) is proven to improve performance  caffeine for short runs  avoiding shiftwork or planning it properly

19. Copyright Catherine M. Burns19 Shiftwork  Circadian Desynchronisation: Shiftwork is counter to circadian rhythms  Issues: alertness, hunger patterns, urinary patterns, quality of sleep, cardiac health, asthsma  Solutions permanent assignment (people don’t usually like this) slow rotation fixed for 2-3 weeks then time to resynchronize between shifts

20. Copyright Catherine M. Burns20 Shiftwork  Shifts should rotate later “delay”  Eg. 12am-8am then to 8am-4pm.  Due to length of rhythm it is easier to adjust to a later shift than an earlier one  Shifts are easier for younger person  Older people have less physiological capacity to adapt

21. Copyright Catherine M. Burns21 People who should not do shift work  Over 40  Cardiac problems  Asthsma  Diabetes  Epilepsy  Past experience with depression

22. Copyright Catherine M. Burns22 Jet lag  UK statistics show that most holiday accidents happen on the drive home from the airport  Drivers 4am-6am have 13 TIMES the accident risk

23. Copyright Catherine M. Burns23 Circadian Resynchronization  Can be artificially stimulated  Cues: Light/dark Food Activity  Exposure to bright light during “daytime”  Full spectrum lights, melatonin?

24. Copyright Catherine M. Burns24 Melatonin studies  Unlike mice, people who are totally blind cannot set the clock in their SCN. As a result, their circadian rhythm drifts out of phase with the actual cycle of day and night. These people often are bothered by feeling sleepy during the day and wide awake when they want to be asleep at night. A recent (12 October 2000) report in the New England Journal of Medicine tells of a group of blind people who were able to set their clocks with the help of a dose (10 mg) of melatonin at bedtime. However, this treatment worked only when the subject's circadian rhythm had drifted so that the normal rise in melatonin from the pineal gland was occurring in the early evening; that is, the dose of melatonin had to be given when it could boost the endogenous level of the hormone.melatonin

25. Copyright Catherine M. Burns25  http://www.sleepfoundation.org/nsaw/sleepiq 99i.cfm