Sleep Health Science and Interventions Flashcards
How much sleep does the average US adult get a night?
6hrs 57mins
37% get <7hrs / night
What % of people get less that 6hrs sleep a night?
20%
List 2 indirect costs associated with insomnia
1) Presenteeism (people at work but not productive)
2) Long-term disability (increased risk)
Generally what is the nightly sleep requirement for most adults?
7-8hrs (no recognised objective test for how much sleep any one individual requires)
Definitions:
a) Circadian
b) endogenous circadian oscillators
c) Entrainment
a) “circa” = about “dia” = day
b) endogenous circadian oscillators = molecules, cells and tissues that comprise the body’s “internal clock”
c) entrainment = the ability to be brought into a rhythm
(synchronisation of internal endogenous oscillators based on external inputs)
Where are the body’s central oscillators found?
the Suprachiasmatic Nucleus (SCN) - the main “body clock”
Where is the SCN located in the brain?
Within the hypothalamus
Where are the body’s peripheral oscillators found?
Every major organ of the body and allow alignment between central and peripheral clocks
(kidneys, liver, heart, adrenal glands and pancreas)
Summarise what ‘circadian rhythms’ are
Biological processes that are regulated by central and peripheral oscillators that are capable of being brought into a rhythm (usually 24h) to help align physiological functions and behaviours with solar light-dark cycles
At what time of day do we experience a cortisol spike?
On awakening / early morning
What provokes the morning cortisol spike?
anticipation of food
(therefore to train the spike to come later, and wake later, can advise to eat breakfast / drink caffeine 45mins after desired waking time)
What is the name of the neuronal tract between the retina and the SCN?
The retinohypothalamc tract
used to entrain central oscillators via light-exposure
There is a neuronal tract between the SCN and what gland which controls melatonin secretion?
the Pineal Gland
(function not fully understood but involved in female reprod / sexual maturity as well as circadian rhythms re sleep / wake cycle -> melatonin)
Splanchnic nerves are part of what aspect of the nervous system?
Autonomic Nervous System -> innervate the adrenal glands
Adrenals glands help to regulate what 3 mechanisms via the hormones epinephrine, norepinephrine, glucocorticoids and aldosterone?
1) Blood flow
2) Temperature
3) Food intake
What are Retinal Ganglion Cells (RGCs)?
Non-visual light-sensitive retinal neurons
What is melanopsin
the photopigment in retina ganglion cells (RGCs)
What type of light is melanopsin maximally sensitive to?
short wavelengths -> blue light
Darkness has what effect on pineal secretion of melatonin?
Darkness triggers melatonin secretion from pineal gland
Melatonin secretion leads to what (vast) operators and outputs?
Cutaneous vasodilation -> peripheral warming -> Cooling of core body temp -> sleep initiation
List 4-5 physiologic changes that occur in EARLY sleep (first 1-4 hours of sleep)
1) Rise in melatonin
2) Slow wave on EEG predominates (restorative)
3) Decreasing core body temperature / increased peripheral
4) Decreased blood pressure and sympathetic tone
5) restorative processes throughout body
List 4 physiological processes that occur THROUGHOUT sleep
FAM
1) DNA remodelling and repair
2) Leptin secretion
3) Gradual increase in cortisol
4) Fatty acid metabolism
List 4 physiologic changes that occur in LATE sleep
1) Declining melatonin levels
2) Longer REM periods
3) Increasing BP, sympathetic tone and baroreceptor sensitivity (ability to change BP rapidly by altering HR, contractility and peripheral vascular tone)
4) Awakening -> cortisol spike
REM periods of sleep play an important role in what psychological process?
Fear extinguishing
What is the predominant entraining force of the SCN clock?
a) Light b) Food c) fluid status d) ambient temp
Light
In what units is light-intensity measured?
Lux
How many lux is bright ‘noon’ sunlight approximately?
100K lux
cloudy: 25K lux; Overcast 2K - 10K lux; full moon 1 lux
How many lux is household lighting approximately?
50-200 lux
(Bright industrial lighting: 1-5K lux
Kitchens & Offices 200-500 lux)
Light in nanometres (visibility) vs Kelvin (colour relative to temperature)
In nm what light range does blue light fall within?
At what temperature is blue seen?
Blue light spectrum: 420-480nm
Blue light dominant at: 6500 Kelvin
Is blue light or orange light dominant at higher temperatures?
Blue light is warmer
blue light: 6500 Kelvin
orange/red: 2500 Kelvin (approx)
What effect does blue light have on melatonin?
Blue light suppresses melatonin
What effects does blue light exposure have - list unto 7 effects?
increases x 4
decreases
suppresses
inhibits
BLUE LIGHT:
1) increases HR, BP, core body temp
2) Decreases sleepiness
3) suppresses melatonin
4) increases cortisol
5) increases sympathetic tone
6) increases altertness
7) inhibits sleep onset and shifts sleep cycle later
(OVERALL leads to delayed phase - like Westward travel)
List at least 3 frequently used items which expose us to blue light (and therefore should be avoided close to bed)
1) Back-lit computers
2) TV screens
3) phones
What impact does low daylight have on the body’s sensitivity of melatonin suppression?
Low daylight INCREASES the SENSITIVITY of MELATONIN SUPPRESSION in response to LIGHT at NIGHT
e.g. 6.5hrs of exposure to 10K lux of light on an overcast day CANNOT fully overcome nighttime melatonin suppression from exposure to 90 lux of light (within household lighting range)
Delayed phase shift i.e. delaying sleep onset can occur with Westward or Eastward travel?
Westward = delayed
Advanced phase shift i.e. early waking can occur with Westward or Eastward travel?
Eastward = advanced
Are ‘night owls’ or ‘morning larks’ more susceptible to melatonin suppression>?
Night owls
Few people have 24h circadian rhythms - do the majority have delayed phase shift or advanced phase shift?
Majority have delayed phase shift
Average SCN clock = 24hr and 8mins
If making daily adjustments to reset forward or back ideally how much time should one:
a) delay exposure to morning light (to reset back)
b) limit light by in the evening (to reset forward)?
a) delay exposure to light by 10mins in morning
b) limit light 20 mins earlier in evening
(in general resets should move by 5-15mins / day)
List 5 metabolic impacts sleep delay / disruption can have?
3 x decrease
2 x increase
1) Decreased calorie burn
2) Decreased leptin
3) Decreased core body temp max
4) Increased appetite
5) Increased insulin resistance
Discuss how timing of and composition of breakfast may be helpful in stimulating morning cortisol and early / effective awakening
Eating a high carb breakfast soon after waking may help:
a) stimulate cortisol rise
b) shift wake-up to an earlier time
3) improve sleep-wakefulness transition (high carb)
If someone is falling asleep too early in the evenings what carbohydrate intervention might be beneficial?
Introducing more carbohydrates at dinner
conversely if falling asleep too late reduce dinner carbs, eat earlier, avoid afternoon snacking
During the afternoon core body temp ___ and peripheral extremities will ___.
During the night the opposite occurs and heat shifts from the ___ to the ___, and HR and cardiac output are ___.
(fill in the blanks)
During the afternoon core body temp RISES and peripheral extremities will COOL.
During the night the opposite occurs and heat shifts from the CORE to the PERIPHERAL EXTREMETIES, and HR and cardiac output are REDUCED.
During what time of day is the blood osmolality at its highest? What does this lead to?
Late afternoon.
Leads to core temp rise (increase in internal temp threshold, increased blow flow to vital organs and less output to peripheral body)
Sleep deficiency has what effect on cortisol secretion during the night?
Sleep deprivation - increases total nighttime cortisol secretion
What effect can ambient temperature have on sleep transition?
If environment is too cold and peripheries are not warm enough transition to sleep may be inhibited.
What effect on the body do the following mimic which may lead to improved sleep:
- benzos
- yoga
- non-sleep meditation
- autogenic training
The body’s natural shift of heat to the extremities
(blood shunted from core to peripheries as sympathetic activation in the muscles and the skin, HR and energy expenditure are all reduced)
Why is fluid status / good hydration important for core cooling at night?
Decrease fluid volume reduced cutaneous blood flow, shunts circulating volume to core and increases cardiac activity / sympathetic tone
What effect can sleep deficiency have on cortisol levels at night and cortisol function?
Sleep deficiency can:
- increase total cortisol secreted at night
- reduce mineralocorticoid function (salt/fluid balance)
List 3 groups of individuals who are more susceptible to melatonin suppression
1) Affective disorders (bipolar / SAD / MDD)
2) Elderly
3) those with corneal opacity (contributes to 2)
What is Behaviourly-Induced Insufficient Sleep Syndorme (BIISS)?
Voluntary sleep deficiency leading to excessive daytime sleepiness/fatigue. Often caused by long working hours / opting for other activities over sleep e.g. TV
Prevalence 7-20%
What 5 associations are there with BIISS?
group, behaviours, routine, affect
Younger adults (30-39yrs) Alcohol abuse Longer working hours (>40hrs / week) Stress Depression
Define insomnia (3)
Difficulty initiating +/- maintaining sleep
Daytime consequences
>/=3months, at least 3 x / week
What physical and mental associations are there with insomnia? (8)
- fatigue / malaise / sleepiness
- mood disturbance / irritability
- poor concentration
- poor memory
- decreased motivation
- increased accidents errors
- headaches / GI distress
- persistent worry about sleep
How is sleep apnoea studied and graded?
Polysomnography (sleep study) is performed and monitors how many apnoeic episodes an individual has in 1hr.
Mild: 5-15
Moderate: 15-30
Severe: 30+
This grading is known as the Apnoea-Hypopnoea Index (AHI)
Give 5 associations with OSA
1) overweight / obese
2) Metabolic syndromes
3) increased neck circumference
4) Loud snoring
5) HTN
How common is restless leg syndrome and what is it associated with (4 things)?
5-15% of US population
Assoc with:
a) periodic movements of sleep (85%)
b) disruptions of sleep
c) fatigue
d) periodic involuntary & jerky movements of limbs while awake or at rest
What is short sleep misconception?
A mismatch between actual sleep duration and interpretation / perception by individual
Give 4 possible causes of secondary insomnia (iatrogenic / physiological)
1) medications
2) vascular dysfunction (peripheral vasospasm / hypoper)
3) visual impairment (opacification / retinal degeneration)
4) renin-angiotensin dysfunction (fluid balance)
What is narcolepsy?
Sudden uncontrollable onset of sleep
Periodic limb movements during sleep (occurring at ~30sec intervals) are more common in what age group?
> 50yrs
Often assoc with restless leg syndrome
Healthy sleep is associated with ___ levels of glucose and cortisol, ___ levels of daytime leptin, ___ insulin sensitivity and ___ food-seeking behaviours.
Healthy sleep is associated with LOWER levels of glucose and cortisol, HIGHER levels of daytime leptin, GREATER insulin sensitivity and REDUCED food-seeking behaviours.
What types of food do we tend to seek if sleep deprived?
carbohydrates
Short sleep duration/disrupted sleep are assoc with what 4 metabolic / weight related features?
Elevated BMI / obesity
Metabolic syndrome
T2DM
Healthy sleep duration is associated with what cardiovascular characteristics?
- lower sympathetic tone & BP
- greater nighttime peripheral perfusion and core body temp cooling
- increased stamina and faster CV recovery time
4 cardiovascular conditions correlated with short sleep
1) refractory / no-reduction of BP in early morning hrs
2) increased heart attacks
3) increase risk CVD deaths
4) vasospastic disorders
In terms of memory and cognition what associations are there with healthy sleep (higher proportion of REM sleep)?
a) enhanced learning and memory
b) faster cognitive processing
c) greater fear / anxiety extinguishment
What is the 3rd stage of sleep which is considered the most restorative stage of non-REM sleep?
slow wave sleep
longer periods = better quality sleep
Impaired sleep leads to reduced brain derived neurotrophic factor (BDNF) - what does BDNF do?
BDNF triggers repair and regeneration of nerve tissue
which area of the brain ins associated with fear extinguishing?
The amygdala
memory and fear
If sleep deprivation occurs with 2 weeks of a traumatic event what effect on PTSD may that have?
Worsening of PTSD symptoms
Healthy sleep duration and quality can help with what cancer risk reducing processes?
DNA repair and histone remodelling
Apoptosis and anti-cancer cytokines (IL-1, IL-2, TNF-alpha)
Impaired sleep can ___ melatonin and immune system, ___ cancer-stimulating cytokines (IL-10), cause gene transcription and cell-cycle ___ and ___ DNA methylation
Impaired sleep can suppress melatonin and immune system, increase cancer-stimulating cytokines (IL-10), cause gene transcription and cell-cycle dysfunction and aberrant (altered) DNA methylation.
What 5 forms of cancer are associated with short sleep / sleep disruption?
1) breast cancer
2) endometrial
3) prostate
4) colorectal
5) Acute Myeloid Leukaemia (AML)
What actions can be taken to help improve bedtime peripheral cutaneous vasodilation to aid sleep?
Bath / shower before bed Socks / heating pad for cold feet Heated blankets / bedding Non-caffeinated drinks (though good to allow gradual cooling of room through the night e.g. window open)
Simple measures to reduce bedroom noise and light…
Black out blinds
Non-digital clocks / quiet clocks
Avoid chargers etc which flash
power naps should be less than…
30mins
What actions may be taken to ensure optimal light exposure during the day / in the evenings to aid sleep?
- Daily sunlight exposure (morning and mid-afternoon)
- Turn off or dim lights at least 1hr before bed (esp blue light)
- Use 2500 Kelvin warm (in colour rather than temp) spectrum light in the evening
What changes to physical activity may be used to aid sleep?
Get up and move at least once an hr
Increase daytime physical activity
increase PA in late afternoon and early evening
What dietary changes can be made to aid sleep?
- Eliminate nighttime caffeine / limit daytime caffeine
- Avoid alcohol 3hrs before bed
- Eliminate after-dinner snacking
- Avoid high sodium foods (esp for dinner - effects vasodilation and vascular tone)
- Assure adequate daytime fluid intake
- weight reduction if elevated BMI
List 3 techniques / pre-bed actions which would be beneficial to the evening routine to reduce stress and aid sleep
(6)
Bath/shower Meditation / mindfulness Guided imagery Music with 60bpm Stop doing stimulating activities 90mins before bed CBT for insomnia
What is 1st line treatment for insomnia
CBT
shown to facilitate getting people off meds and sustain sleep over time
Which of the following behavioural therapies meets evidence-based psychological treatment criteria for adults >60yrs with insomnia:
1) Sleep restriction therapy
2) Stimulus control therapy
3) Relaxation-training therapy
4) Sleep hygiene
Sleeping restriction therapy
Others all shown to be effective in mod-high quality RCTs though
What is sleeping restriction therapy?
A method which aims to reduce number of non-sleeping hours in bed achieved by reducing overall time in bed. e.g. aim for 5 or 6 hours in bed initially and once a patient begins to feel they are spending most of that time asleep and wish for more can increase amount of time in bed by 15mins / day max.
To a point induces sleep deprivation which aids long-term deeper, better quality sleep
Describe how stimulus control therapy can be used in insomnia
(NB: if someone spends hours tossing and turning in bed they begin to associate bed with being awake and stressed. Conditioning therapies attempt to brake this cycle)
If you cannot fall asleep in 20mins:
- get up, go to another room and do something relaxing such as reading until you feel sleepy
- then return to bed. If still cannot sleep within 20mins repeat
AVOID reward-based/stimulating activities including:
eating; TV; studying; house chores; account balancing
Set alarm for same time every day
Avoid napping
Which of the following statements about supplemental melatonin are true:
- Proven to be highly efficacious in insomnia
- shown to be efficacious in jetlag mitigation
- efficacious in circadian rhythm disorders
- no drug interactions have been demonstrated
- suppresses endogenous melatonin
- typical doses 1-6mg
TRUE:
>Efficacious in jet lag (sustained prep more helpful in Westward travel)
>Effective in circadian rhythm disorders
> Typical doses are 1-6mg
NOTE:
- mixed evidence for insomnia
- may interact with cytochrome P450 drugs
- doesn’t appear to suppress endogenous melatonin
- S/L preps better bioavailability
List some risks associated with prescription strength hypnotic medications (e.g. diazepam, lorazepam, zopiclone, Benadryl, doxylamine)
- increase death rates in 18-55yr olds
- Increased risk of all-cause mortality all age groups inc:
OD, Suicide, accidents, falls, depression, cancer;
(Not in TB: tolerance over time; higher dose may cause CNS depression. Short term use can be appropriate but problems can occur if used longer than 7-10 days)
If you are a morning lark and wish to stay in bed a little longer what measures might you take?
- increase late evening light exposure (sunlight / blue 6500 kelvin light)
- increase evening exercise
- avoid bright light until ideal waking time
- avoid eating or drinking caffeine until 30-60mins after ideal waking time
- shift carbs from breakfast to dinner
- ensure bedding will keep warm in early morning
What actions might aid Jetlag when travelling EAST?
EASTWARD = harder, reduces hours in the day
- exposure to bright light close to new ideal wake-up
- dim-light exposure starting 1hr before new ideal sleeptime
- eat hearty breakfast within 30-45mins new ideal wake-up time
- 1mg SL melatonin 1hr before ideal sleep time
What actions might aid Jetlag when travelling WEST?
WESTWARD = increases hours in the day
late afternoon / early evening bright light pref outdoors
avoid dim-light exposure until 1hr before new sleep time
hearty breakfast within 30-45mins ideal new wake
eat complex carb-rich dinner 2-3hrs before ideal sleep
1mg melatonin 1hr before sleep
7 points of a mini-sleep assessment…
1) typical weekday hours sleep
2) typical weekend day hours sleep
3) perceived sleep quality
4) RED flags
5) frequency of daytime fatigue / sleepiness / diff waking
6) frequency and type of sleep disturbance
7) Attitude and barriers to sleep
What are the 5 RED FLAGs of poor sleep habit?
1) <7hrs sleep
2) 1+ hrs difference between weekday and weekend sleep duration
3) Irregular sleep timing / duration (e.g. shift work)
4) poor sleep quality despite 7+ hrs sleep
5) >9hrs sleep
What is the STOP assessment for OSA?
Snoring (LOUD)
Tired often - inhibits daytime functioning
Observed apnoeic episodes
Pressure (HTN / taking meds for)
2+ = HIGH risk -> Refer for sleep study
What 10 points should a sleep hygiene assessment address?
1) daytime naps >30mins
2) poor daytime hydration
3) variations in sleep (onset/offset)
4) prolonged non-sleep periods in bed
5) Stimulating activities pre-bed
6) going to bed stressed, angry or upset
7) reading, watching TV, eating in bed
8) uncomfortable bed +/- bedroom
9) think, plan, worry in bed
10) caffeine, alcohol within 3hrs of bed
Light during the day (blue light) _____ melatonin and ____ alertness.
Light during the day (blue light) SUPPRESSES melatonin and SUPPORTS alertness.
Low daylight decreases what 4 things?
1) daytime activity
2) alertness
3) positive affect
4) core body temperature
What functions does cortisol help support / control within the body?
- stress (fight or flight) response
- BP/circulation
- halts non-essential processes e.g. reprod/immune/growth
- emotional arousal (fear / anger)
- increases blood sugar / insulin resistance
- supports nervous/immune/skeletal/digestive/circ systems
- anti-inflammatory (hence corticosteroids used in inflammatory conditions)
