Sleep Disorders

Starter questions What is a sleep disorder? Can you name any?

Answers What is a sleep disorder? Can you name any? Problems falling asleep, staying asleep, or staying awake during the day. Can you name any? There are 100s!

Circadian Rhythms Sleep Disorders The disruption of biological rhythms can have negative physiological and psychological effects as the internal biological clock attempts to readjust Things that disrupt our biological rhythms are: Jet lag Shift work (this is relevant to your assessment)

Circadian Sleep Disorders Circadian rhythm sleep disorders all involve a problem in the timing of sleep - when the person is awake and when they are asleep The circadian clock is set by exogenous zeitgebers e.g. light/dark. This keeps us synchronized to the 24/h day Jet lag and Shift work can lead to Circadian rhythm sleep disorder & involves at least one of the following problems: You have a hard time initiating sleep, you struggle to maintain sleep, waking up frequently during the night Wake up too early and are unable to go back to sleep Sleep is non-restorative or of poor quality

Jet Lag….The Facts. Jet Lag only occurs when flying from East-West or from West to East. in other words when we change time zones. Jet Lag does not occur form North-South and vice versa!! Symptoms Tiredness Irritability Concentration problems Anxiety Example You fly from Scotland –Boston (USA). You leave at 11am arrive 5pm British time actually it is 12pm in Boston...by 8pm Boston time you’ll be tired as it is 1am to you normally!! Your body is preparing for sleep but the external time givers tell you it’s only early evening. Your biological clock has become desynchronised from external zeitgebers

Disruption of biological rhythms: Jet Lag….. Circadian sleep disorders Travelling from East to West means your body clock is ahead of local time. e.g. we feel like it’s 1am but local time is 8pm This is an example of phase delay (local time behind us) Travelling from West to East means your body clock is behind local time and you are not ready to sleep yet e.g. our body clock thinks it 7pm but local time is midnight. This is an example of phase advance (local time ahead of us) By delaying/advancing our rhythms we are compromising our ability to cope in the short term. Resynchronisation Evening when there is radical resynchronisation from Jet Lag the SCN (master clock) will gradually adjust to the changed time of day This takes time however and the symptoms of jet lag can last several days

Research into Jet Lag Recht et al (1995) Baseball / Travelling to games (3 year study) Travelling West to East, American Baseball teams won 37% of games Travelling from East to West, they won 44% of games Recht et al concluded that jet lag affected the players’ performance – the effects were worse after phase advance Evaluation? Too many uncontrolled variables e.g. ability of other team Waterhouse et al (2007) reviewed 500 articles on aviation & health Found that disrupted sleep patterns led to cabin crew experiencing decreased cognitive performance (e.g. memory) Also found a link with Mental health problems and Menstrual cycle problems Confirmed that jet lag can lead to problems with cognitive process, and directly affect brain function & physiological processes e.g. stress

Jet Lag…How can we reduce the impact/effects of Jet Lag? Any ideas? Use melatonin to reset the body clock.. As we know Melatonin plays a crucial role in the SCN that controls biological rhythms Melatonin has been shown to reduce the effects of jet lag Should not be used unless intending to stay in new time zone over 3 days. Timing is important too...individuals should be allowed to sleep after the melatonin…. If not they are prolonging their circadian rhythm. There is little scientific evidence on flying performance and melatonin however….cabin crew who have ingested melatonin are not allowed to fly within 36 hr Other ideas… Adopt local eating times etc to help reset the biological clock as soon as possible.

Disruption of biological rhythms: Shift Work… Circadian sleep disorders Working at times when people are normally asleep, and being asleep at times when people are normally awake, causing breakdowns between internal biological clocks & external cues Rising early or retiring to bed earlier than normal is an example of phase advance. Going to bed late or getting up late is an example of phase delay. When we work at night we are going against out circadian rhythms – trying to maintain alertness when our biological clock is imposing sleep on the brain! However shifts patterns change regularly, meaning workers can be in an almost permanent state of desynchronisation On average it takes 3 days to adjust to a 12 hour shift in time. This is not long enough time for resynchronisation

Disruption of biological rhythms: Shift Work… We need doctors, nurses, policeman etc…so what happens to their cycle when it is disrupted by shift work? Any ideas? High illness rates, sleep disorders (insomnia) and elevated levels of stress and...accidents! Chernobyl occurred between 1am & 4am. Most lorry accidents occur between 4am & 7am. The Exxon Valdez oil tanker ran aground at 12.04am in 1989 – 10 million gallons of oil spilled Evidence: Hawkins and Armstrong-Esther (1978) studied 11 nurses during a 7 night rotation of their duty. Performance was significantly impaired on the first night but improved through the week. (Temps did not adjust until last night!)

Shift work & illness/sleep disorders Czeisler et al. (1982) studied shift workers at a factory in Utah They found high illness rates, sleep disorders and elevated levels of stress, suggesting that their internal body clocks were out of synchronisation with exogenous zeitgebers Researchers persuaded management to move to a phase-delay system of rotating shifts forward in time, to reduce negative effects. Shift rotations were adjusted to every 21 days, instead of 7 days, giving time for adjustment. Nine months later, workers appeared healthier, more content and output was up, showing how psychological research can lead to practical applications incurring positive outcomes Evidence that 7 days is not enough time for the body to readjust

Disruption of biological rhythms: Shift Work… Consequences Shifts workers tend to be awake late evening and/or early morning and sleep during the day. After a shift change people take a week to adapt to the new regime, Unless workers succeed in resetting their biological clocks they experience sleepiness at work and insomnia at home Social constraints may tempt workers to stay awake when they should be sleeping (Especially kids) People who are working shifts are often sleep deprived because they find it hard to sleep when there is light outside and its noisy

Shift work & sleep disorders Treatments available? Czeisler et al (1990) Bright lighting in the work place seems to be key to helping workers to adapt to new shifts so that they are alert at work and sleep well during the day Light Box – Bovin et al (1996) Melatonin

Treatments for Jet Lag & Shift Work Boivin et al (1996) put 31 male participants on an inverted sleep pattern (so they were awake at night and slept during the day) for three days.  Each day when they woke they were sat in front of dim lights for 5 hours and then placed in one of four conditions: 1.Very bright light, 2.Bright light ,3.Ordinary room light , 4. Continued dim light. Core body temperature was recorded and used as a measure of how well they were adapting to the new rhythm. After three days: Group 1 had advanced by five hours (they were adapting to the new pattern best) Group 2 had advanced by three hours. Group 3 had advanced by one hour. Group 4 had drifted backwards by one hour (were failing to show any signs of adapting). 

Boivin et al (1996) Conclusions?? Artificial light can help us adapt our biological rhythms to suit the environment, however, brighter light is even more effective. Clearly, this useful in the workplace to help shift workers to adapt to changing sleep-wake cycles.

Shift work can lead to other… Circadian Rhythm Sleep Disorders

Activity You now know about 2 circadian sleep disorders Jet Lag ; Shift work disorder Find out about one of the following: Primary insomnia Secondary insomia Advanced sleep phase disorder (ASP) Delayed sleep phase disorder (DSP) Non–24-hour sleep-wake syndrome

Insomnia Insomnia is the most common of the sleep disorders Some people have problems sleeping, either in the quality of sleep or length of sleep. This means that sleep is non-restorative and leads to day time tiredness and irritability, affecting work and social functioning. It can lead to depression. The diagnostic criteria for insomnia are: taking more than 30 minutes to fall asleep; sleep efficiency (the ratio of total sleep time in bed compared with amount of actual sleep) of less than 85%; increased number of night-time awakenings; symptoms occurring more than three times per week.

Activity Using the following website, find out how chemical stimulants and depressants can affect sleep http://healthysleep.med.harvard.edu/healthy/science/how/external-factors

Factors affecting Sleep: Chemical Stimulants Many common chemicals affect both quantity and quality of sleep. These include caffeine, alcohol, nicotine, and as well as prescription medications including beta blockers and antidepressants As we know The longer you are awake, the stronger the sleep drive becomes Interestingly, caffeine, the world’s most widely used stimulant, works by temporarily blocking the sleep drive in specific parts of the brain (SCN) If sleep does occur following the intake of caffeine, the stimulant’s effects may persist for some time and can influence the patterns of sleep – can lead to more awakenings http://healthysleep.med.harvard.edu/healthy/science/how/external-factors

Factors affecting Sleep: Depressants Alcohol is a depressant of the Central Nervous System Alcohol is commonly used as a sleep aid. However, although alcohol can help a person fall asleep more quickly, the quality of that individual's sleep under the influence of alcohol will be compromised. Ingesting more than one or two drinks shortly before bedtime has been shown to cause increased awakenings—and in some cases insomnia This is due to the arousal effect the alcohol has as it is metabolised later in the night Alcohol can become a stimulant as our bodies process it –so you may wake up half way through the night