Sleep deprivation

Question 1

What is sleep deprivation

Answer 1

Actively restricting sleep by going to bed late, waking up early or getting up in the night

Question 2

Why does sleep deprivation occur?

Answer 2

Shift work, jet lag, lifestyle, sleep disorders, stimulants, family commitment, anxiety

Question 3

Types of sleep deprivation

Answer 3

TSD - short term is <45 hours
Long term is >45 hours

PSD - acute and chronic

Sleep fragmentation - go to bed at normal time but sleep is disrupted through night meaning less time in SWS and more time in light stages

Question 4

Consequences of sleep deprivation

Answer 4

Cog function
Emotional wellbeing
Weight management 
Neurodegeneration
Immune system
Reproductive system

Question 5

What study looks at cog function

Answer 5

Van dongen et al 2003

Question 6

What study looks at neurodegeneration

Answer 6

Bianchi et al 2014

Question 7

What study looks at weight management

Answer 7

Van couter et al 2005

Taheri et al 2003

Question 8

Van dongen et al 2003

Answer 8

Used a range of deprivation periods ranging from TSD to 4, 6, 8 hour sleep
Assessed cog function through tasks, psychomotor vigilance task, TSD had sig lower reaction time

On digit symbol substitution task, sig lower score

Question 9

What study looks at emotional wellbeing

Answer 9

Yoo et al 2007

Question 10

Yoo et al 2007

Answer 10

26 health participants aged 18-30
Sleep deprived for 35 hours, and other group not deprived
Emotional stimulus viewing task whilst brains fMRI scanned
Sleep deprived had 60% greater amygdala activity - amygdala is part of brain involved in emotional response
Thus are more sensitive to negative events when sleep deprived

Question 11

Van couter et al 2005, Taheri et al 2003

Answer 11

Grehlin and leptin are hormones that regulate appetite: if sleep deprived, leads to changes in eating patterns and food choice

Ghrelin:
made by cells in stomach
increases appetite for high calorie food
increases drive to eat
fast acting hormone
In deprivation, grehlin production increases: leads to weight gain.
Research shows single night of deprivation can increase ghrelin levels

Leptin:
made by white fat cells in body
surpresses appetite by communicating to brain that it has enough energy it needs to function
In deprivation, body surpresses leptin production making us more likely to feel hunger

Question 12

Effect on immune system

Answer 12

Same impact as stress = weakens immune system and ability to fight infections in blood stream
Natural killer cells in blood stream = help fight viruses, illnesses, infections = when deprived, reduce number
Chronic deprivation, increases risk of developing diseases like cancer

Question 13

Bianchi et al 2014

Answer 13

Poor sleep –> beta amyloid build up (toxic protein) –> neuron death synapses loss –> cognitive decline
SWS associated with removing this, but bad sleep means less time in SWS

Question 14

Dawson & Reid 1997

Answer 14

Effects of sleep deprivation in comparison to alcohol
Ppts awake for 28 hours
Assessed psychomotor performance at 30 min intervals using computer administered task of hand eye co-ordination

Other group asked to consume 10-15g alcohol every 30 mins from 8 am until blood concentration 0.10

Longer you’re awake, worse performance is: similar to drunk

Question 15

How much sleep is necessary?

Answer 15

Ferrara and De Genarro 2011:
suggest 7-8 hours sleep but no real consensus
Optimum amount of sleep isn’t universally accepted, have to observe individual differences

Question 16

Limitations of studies

Answer 16

Napping
Practise effects
Individual differences: age, gender, genetics, circadian rhythm
Divergence between subjective and objective measures
Different paradigms make it difficult to make comparisons, especially for PSD