Sleep Deprivation Flashcards
Reasons for sleep deprivation
shift work = affects your sleep cycle and can lead to sleep deprivation
sleep disorders
lifestyle - 24/7 society: internet and mobile phones
family commitment - young children
anxiety - increases arousal
stimulants - hinder ability to get to sleep
How much sleep do we need?
test this by carrying out sleep deprivation studies
- -> these studies reveal the functions of sleep, they also are useful in informing us about the impact of sleep loss = helps us answer the question
- -> commonly told about 8 hours BUT this is not clear cut (Ferrara & DeGennaro, 2001)
Chronotype?
morning or evening person
What is sleep deprivation?
Define
Insomnia define
sleep deprivation = an active period where we actively restrict our sleep either by going to bed late, waking up early or getting up through the night
insomnia = when an individual struggles to get to sleep and maintain sleep over night
v different but consequences of both are very similar
Different types of sleep deprivation?
Total sleep deprivation (TSD)
- short term = being awake for up to 45 hrs
- long term = being awake for more than 45 hrs
(not used nowadays due to ethical issues)
Partial sleep deprivation (PSD)
- sleep is restricted
- short term (Acute)
- long term (chronic)
Sleep fragmentation = going to sleep at the usual time but your sleep is disrupted throughout the night = might end up spending more time in the lighter stages of sleep eg. stage 1
–> after this you don’t feel well rested. leads to less time in deep sleep (3+4)
Signs of sleep deprivation
a whole range of physiological and psychological consequences
- difficulty making simple decisions
- difficulty concentrating
- falling asleep
- weak immune system
- feeling more emotional than usual
- still feeling hungry after eating
Consequences of sleep deprivation
- physiological consequences? (Chittora et al, 2015)
- cognitive function
- emotional wellbeing
- weight management
- reproductive system –> affects testosterone and sperm quality
- immune system
Chittora et al 2015:
- brain structure affected
- verbal disturbances
- impaired learning, poor decision making, mental fatigue (may be due to abnormal function of prefrontal cortex)
Physiological
- 6-8% decrease in brain metabolic rate
- aching muscles
- headaches
- increase blood pressure
- increase risk of diabetes
- obesity
- seizures
How do we study sleep deprivation
- can select naturally sleep deprived participants so we don’t have to sleep deprive people
- most use within subjects design
- usually 7-14 days (one time measurement may just be a one-off bad nights sleep)
Sleep deprivation and cognitive function
Van Dongen et al, 2003
looked at:
sleep deprivation effect on cognitive performance range:
TSD / 4 hrs / 6 hrs / 8 hrs of sleep
4 tasks:
1) psychomotor vigilance test
2) digit symbol substitution task
3) Stanford sleepiness scale
4) serial addition subtraction task
found:
1 - those in TSD took longer and had slower reaction time (more sleep = better performance)
2 + 4 - TSD did significantly worse (more sleep = better performance)
3 - TSD are clearly able to identify when they are sleepy. Interestingly, the other groups with restricted sleep (+poor performance) didn’t identify as sleepy
= we are not subjectively accurate in identifying our level of sleepiness
(sleepiness scale doesn’t correlate with other measures)
SAME STUDY, also observed sleep structure/ architecture following in the restricted sleep conditions
1 = v little difference in amount of time spent here
2 = 4hr sleep group spend less time here (sacrifice stage 2)
3+4 = v little difference of time spent in SWS –> shows the importance of SWS = important function
REM = 4/6hr group spend less time in REM than 8 hr group = SWS prioritised
(DELTA POWER = increase in delta power means an increase in amount of delta activity over other electrical activity)
Sleep deprivation and sleep homeostasis
circadian rhythm = body clock
sleep homeostasis = sleep pressure
–> when sleep deprived, sleep pressure continues to build and keeps increasing. The longer you stay awake the more it increases
- v important as sleep homeostasis is v closely related to SWS. Because, the greater the sleep pressure, the more quickly an individual will enter SWS and spend more time in SWS
(MORE sleep pressure = MORE SWS)
Sleep deprivation and emotional wellbeing
(Yoo et al)
SD + mood?
Yoo et al (2007)
sleep deprived (35hrs) and control
- used FMRI while p’s viewed emotional stimulus viewing tasks
found:
-both groups had increased activation to negative stimuli
-sleep deprived group had 60% greater amygdala activity
SD + MOOD:
- we become more sensitive to nehative events when we are sleep deprived –> because of the amygdala (region involved in emotional responses)
- the extent of amygdala engagement can be influenced by the medial prefrontal cortex (MPFC). It is proposed to exert inhibitiory, top down control of amygdala function
- sleep dep may show decreased emotional intelligence and deteriorated interpersonal relations (lower empathy and positive thinking)
Sleep deprivation and weight management
good sleep ensures:
- keep appetite in check
- curb cravings
- reduce late night snacking
PSD can impact how easily weight is: gained, lost and maintained
2 key hormones:
1) Ghrelin
2) Leptin
- sleep is important for regulating our metabolism and regulating these hormones
- sleep deprivation disrupts the levels of 2 hormones –> these are critical in regulating hunger and appetite
= changes eating patterns and food choices
GHRELIN:
-fast acting hormone
- produced in cells of the stomach
- INCREASES our drive to eat (specifically high-calorie food)
(sleep deprivation = increase ghrelin production, therefore appetite)
LEPTIN:
-produced in white fat cells throughout body
- SUPPRESSES appetite by communicating to brain that the body has the energy it needs to function
(sleep deprivation = decrease leptin production = feel ongoing pangs of hunger)
Even short term sleep deprivation has been shown to decrease leptin production
LINKED to obesity and public health
Sleep deprivation and immune system
same impact on immune system as stress (essentially mimics stress)
- weakens immune system and ability to fight infection
- natural killer cells = found in blood stream. They help fight infections and illnesses
- literature shows sleep deprivation reduces the number of natural killer cells (so, tired/ run down = struggle to fight illness)
- chronic sleep deprivation increases the risk of developing diseases such as cancer
Sleep deprivation and neurodegeneration
lack of sleep leads to an increase in development of a toxic protein called: BETA AMYLOID (associated with Alzheimers disease)
STAGES:
- beta amyloid build up due to poor sleep
- neuron death, synapse loss
- cognitive decline, Alzheimers disease
–> SWS associated with removing toxins including beta amyloid (less sleep = more build up) =greater risk of dementia
- Chittora et al (2015)
- altered expression of structural genes
Sleep deprivation Vs Alcohol consumption
p’s kept awake 28hrs OR 10-15g alcohol consumed at 30 min interval until blood alcohol reached 0.10%
- cognitive psychomotor performance assessed at half hourly intervals
- the longer you are awake the worse the performance gets = similar to alcohol
