This page is self explanatory and sets the scene for the remainder of the presentation – Sleep is a critical health issue. It has become more important in recent decades – as 24/7 has come upon us. Teenagers and old people have different sleep physiologies and needs – the presentation does not mention that much.
The invention of the electric light bulb is credited with many of our sleep problems! Sleep problems are directly implicated in many health problems.
Sleep problems rank high relative to other health problems – they are NOT trivial.
Sleep deprivation is a relative concept. Small amounts of sleep loss (eg, 1 hour per night over many nights) have subtle cognitive costs, which often go unrecognized by the individual experiencing the sleep loss. More severe restriction of sleep for a week leads to profound cognitive deficits similar to those seen in some stroke patients, which also appear to go unrecognized by the individual. The lack of recognition of the effects of sleep deprivation appears to be a constant feature.
Short-term sleep deprivation has been implicated in contributing to obesity as well as glycemia dysregulation contributing to poor control of type II diabetes.
As the function of sleep has not been fully determined, the absolute number of hours necessary to fulfill its function is still unknown. Some individuals claim full effectiveness with only 3-5 hours of sleep per night, while some admit needing at least 8 hours of sleep per night (or more) to perform effectively. Sleep deprivation is therefore best defined in terms of the tasks impaired. With decreased sleep, higher-order cognitive tasks are affected early and disproportionately. Tests requiring both speed and accuracy demonstrate considerably slowed speed before accuracy begins to fail.
‘‘Dead Tired’Dead Tired’
Members of the DoL PsychosocialMembers of the DoL Psychosocial
Panel MembersPanel Members
• Dr. John Kerr
Occupational Physician, Hastings
• Rachel Irwin
Clinical Psychologist, Wellington
• Dr. Mark Floyd
Occupational Physician, Wanaka
• Shona Kelly
Occupational Health Nurse, DoL, Whangarei
• Frank Darby
Technical Leader, DOL, Wellington
• Scene Setting John Kerr
• Physiology of Normal Sleep Rachel Irwin
• Physiology of Sleep Deprivation Shona Kelly
• Workplace Effects Frank Darby
• Sleeping Well Frank Darby
• Conclusion John Kerr
1 Scene Setting - Relevance1 Scene Setting - Relevance
• Sleep is the third pillar of health – food, nutrition and sleep
• Fatigue kills
• Sleep is critical to:
– workplace safety and
• Increasingly we are living in a 24 hour society
• Different age cohorts have different sleep requirements
– Older people
• It is the most common medical disorder
2 Scene Setting - Historical Facts2 Scene Setting - Historical Facts
• In US 90 minutes less sleep per night in 2010 compared 1900
• Recent US study 90% presenting to GP had sleep related
• Sleep loss and poor sleep are significant factors in:
– Memory & memory consolidation/Concentration/Learning/Work
– Many others no doubt
3 Scene Setting - Outcomes3 Scene Setting - Outcomes
• Sleep disorders rank in the top ten risk factors
for health conditions, and exceed such factors
as alcohol or unsafe sex!
• Equals annual estimated cost of asthma!
• Effective treatment measures are available
Physiology of Normal SleepPhysiology of Normal Sleep
1 Physiology of Normal Sleep1 Physiology of Normal Sleep
NREM (Non - Rapid Eye Movement).
• Stage N1 – transition between wake and sleep
– Drowsy state, high muscle tonus, and absence of rolling eye movements
– Occurs upon falling asleep and during brief arousal periods within sleep
– 2-5% of total sleep time
• Stage N2
– Decreased muscle tonus
– Occurs throughout the sleep period
– 45-55% of total sleep time
2 Physiology of Normal Sleep2 Physiology of Normal Sleep
• Stage N3 – delta or slow wave sleep
– Most restful phase
– Occurs mostly in the first third of the night
– 5 to 15% of total sleep time
3 Physiology of Normal Sleep3 Physiology of Normal Sleep
REM (The rapid eye movement phase)
• Active brain activity, absent muscle activity, rapid eye
movements and dreaming
• Occurs in 4-5 episodes throughout the night
• 20-25% of total sleep time
• Increases in duration throughout the night from <10 min to >60
• NREM-REM cycles vary from 70-100 min initially to 90-120
4 Physiology of Normal Sleep4 Physiology of Normal Sleep
• Circadian rhythms help coordinate body functions for
• Suprachiasmatic nucleus (SCN) sets the clock to
approximately 24.2 hours
• SCN receives information on light and dark from the
eyes and regulates body functions
• Activity becomes random if SCN destroyed
5 Physiology of Normal Sleep5 Physiology of Normal Sleep
• Body temperature
• Alertness – reaction time and cognitive reasoning
• Kidney function, hormone secretion, blood pressure and
Effects of Sleep DeprivationEffects of Sleep Deprivation
1 Sleep Deprivation – effects on people1 Sleep Deprivation – effects on people
• Decreased resistance to disease caused by a decrease in immune
system function as measured by:
– white cell count and activity
• Increased inflammatory markers including
– C reactive protein, an indicator of acute or chronic health problems
• Decreased circulation
• With sleep apnoea an increased risk of myocardial infarct (heart
• An increased risk by 3- 4 times of stroke
2 Sleep Deprivation - effects on people2 Sleep Deprivation - effects on people
• Decreased insulin production and increased glucose blood levels
• Increased risk of impaired glucose tolerance and type II diabetes
with inhibition of secreted insulin from the pancreas
• Glucose-PET studies in individuals deprived of sleep have shown
that after 24 hours of sustained wakefulness, the metabolic activity
of the brain decreases significantly (up to 6% for the whole brain
and up to 11% for specific cortical and basal ganglionic areas).
3 Sleep Deprivation - effects on people3 Sleep Deprivation - effects on people
• Impaired appetite control in the hypothalamus leading to
– increased hunger/appetite …caused by
– decreased leptin production (the hormone that turns off hunger)
• Sleep < 7 hours per night leads to an increased risk of obesity
4 Sleep Deprivation - effects on people4 Sleep Deprivation - effects on people
• A decrease in core body temperature
• Increased heart rate variability
• Mood changes associated with depression
• A decrease in the release of growth hormone.
5 Sleep Deprivation - effects on people5 Sleep Deprivation - effects on people
• “Delayed phase insomnia” is caused by growth hormone production
in puberty where teenagers don’t feel sleepy till much later than
normal due to a delay in their circadian rhythm.
• Chronic insomniacs tend to think that they are awake a lot of the
time that they are actually asleep and this often contributes to their
anxiety and hence sleep deprivation.
1 Workplace Effects - Prevalence1 Workplace Effects - Prevalence
• Gander et.al. June 2001.
– 27% of NZers reported a current sleeping problem.
• Te Ropu Rangahau Hauora a Eru Pomare and the Sleep Wake
Research Centre. April 1999.
– 37% rarely/never got enough sleep
– 46% rarely/never woke feeling refreshed.
– Maori reported more sleep problems and greater daytime sleepiness
2 Workplace Effects – Sleep disorders2 Workplace Effects – Sleep disorders
• Over 70 Sleep disorders:
– Obstructive sleep apnea syndrome (OSAS)
– Restless legs syndrome
– All compromise daytime alertness.
• Inadequate Sleep - leads to or affects -
– Tiredness and lethargy
– Performance deficits
• Memory and concentration
• Attention span
• Complex thinking
– Mood changes
}These 3 most common
3 Workplace Effects – Costs - 13 Workplace Effects – Costs - 1
• Conclusions of Hillman et. al. 2006
– “The direct and indirect costs of sleep disorders are high. The total financial cost
(excluding suffering) of $4.5 billion represents 0.8% of the Australian GDP. The
cost of suffering of $3.0 billion is 1.4% of the total burden of disease in Australia.
Total = $7.5 Billion (2006)
– Sleep disorders rank in the top 10, above alcohol and unsafe sex.
– Sleep disorders contribute: - 9.1% of workplace injuries; - 8.3% of depression; -
7.6% of motor vehicle accidents; - 2.9% diabetes; - 2.1% hypertension
– Direct health costs are 2% of $7.5 billion
not enough being done.
– Spending on health disorders similar to that on asthma.
The Economic Costs of Sleep
Disorders. Hillman et. al.
Sleep. Vol. 29. No. 3. 2006
4 Workplace Effects – Costs - 24 Workplace Effects – Costs - 2
Hillman et. al.
• Motor vehicle crashes - $0.8B
• Workplace incidents - $2B
• Productivity Costs - $1.2B
• Studies examining
– the effects of OSAS on MVA
– the effects of treating OSAS on MVA
• At least 112 lives saveable in
Australia each year
Gander et. al. 2010.
• Annual costs of OSAS for NZers (aged 30 –
60) are estimated at $40 million or $419 per
case – with accidents a major contributor.
• The estimated incremental net cost of
treating OSAS was $389 per case treated,
giving an estimated incremental net direct
medical cost per quality of life year (QALY) of
• This is well below the average QALY cost of
$6865 for drugs selected by PHARMAC for
5 Workplace Effects – Prevention5 Workplace Effects – Prevention
• Information and training
– Sleep disorders and sleep quality
– Shiftwork management
– Rest breaks and Napping
• Health monitoring for staff
– For sleep disorders
– For sleep quality
Safety Critical Industries
1 Sleep Hygiene – Physical1 Sleep Hygiene – Physical
• Sleep in a dark (alkathene), cool room, in a warm,
• Control noises.
– Which is more likely to wake you up – traffic (once you get used to it) or
a helicopter flying over? Why? What is the significance of the answer?
– When does noise compromise sleep the most?
• Help wake up with sunlight – go outside.
• Use sunglasses on the way home if you work shifts.
2 Sleep Hygiene - Food2 Sleep Hygiene - Food
• Avoid before bed:
– Heavy food
– Spicy food
– Lots of food in the stomach
– Smoking, Caffeine and Alcohol before bed
• If it dissolves in water – good for night shifts.
33 Sleep Hygiene - ExerciseSleep Hygiene - Exercise
• Get regular exercise each day.
– Before dinner or in the morning.
• How can exercise help you sleep better?
• When is exercise best for sleep?
A fact not well known: People sleep better than they think. When people
who have spent a night in a sleep laboratory are shown evidence of their
sleep/wake distribution they usually express surprise.
Conclusion: we sleep better than we think we do!
4 Sleep Hygiene - Technique4 Sleep Hygiene - Technique
• We can’t make ourselves fall asleep – so this section is about
helping the conscious brain to cease its activity
– Learn to relax if you need to (there are many methods).
– Deal with problems - as you can - before going to bed.
– Reserve the bedroom for sleeping.
• No TV, telephoning, hobbies, studying. (!) Why?
– Nap before 2pm, for not more than 20 minutes.
– Avoid sleeping pills and alcohol.
– Seek professional help if you need to.
– If you can’t sleep, get up.
5 Sleep Hygiene - Routine5 Sleep Hygiene - Routine
• Regularity – aim for 8 hours.
– Go to bed and get up at the same time each day.
• Adopt a pre-sleep routine.
– Avoid stimulating activities before bed.
– Go to bed only when sleepy
• Don’t nap in the evening.
• Aim to sleep (nearly) all the time you are in bed.
– Bedrooms need to become associated with the pleasant experience of
sleeping, (as opposed to worrying).
4 Scene Setting - Conclusion4 Scene Setting - Conclusion
Sleep is critical to:
– Workplace safety and
“Early to bed, early to rise keeps a man healthy
wealthy and wise”