L3 Sleep Deprivation Flashcards
(34 cards)
What are some reasons for sleep deprivation?
Stress/anxiety Environment Drugs Blue light Shift patterns Age Young children in the family Sleep disorders/health conditions Lifestyle
Difficult to control for everything
How much sleep do we need?
There are so many individual differences, and chronotype preferences
There is not a set amount as it varies between each person
What is sleep deprivation?
Actively stopping sleep by going to sleep late, getting up early etc. - often broken down into 3 types
Different to insomnia!! which is a struggle to get to sleep and maintain sleep - but they have very similar negative effects
What are the 3 types of sleep deprivation?
TSD = ST <45 hours, LT >45 hours - it is difficult to run studies with TSD due to micro-sleeps and ethics
PSD = can be acute (a few days) or chronic (years)
Sleep fragmentation = wake up a lot and keep entering stage 1 sleep instead of deep sleep - don’t feel well rested the next day
What are some signs of SD?
irritable, low energy, slower cognitive ability, difficulty making simple decisions, falling asleep, still hungry after eating, emotional, weakened immune system
How does SD affect the reproductive system?
If a young male is sleep deprived then he will have similar testosterone levels to a man in his 80s. The quality of sperm is also similar
What did Van Dongen et al. (2003) do to investigate cognitive function?
had 4 groups assessed in different SD conditions:
1. TSD 2. Slept for 8 hrs
3. Sleep restricted to 6 hrs 4. Sleep restricted to 4 hours
Had multiple measures of cognitive function to make it a stronger design (psychomotor vigilance test, digit symbol substitution task, serial addition subtraction task, Stanford sleepiness scale)
What was seen in the psychomotor vigilance test?
Was good for this kind of study as there are no practice effects
The TSD group had the most errors with the 8 hour sleep group performing the best
As sleep reduced, performance got worse
What was seen in the digit symbol substitution task?
The TSD group ended up with a negative total value due to the number of errors. The more sleep they had the better the performance
What was seen in the serial addition subtraction task?
Showed very similar results to previous tasks, making the results more reliable
What was seen in the Stanford sleepiness scale?
Subjective self-report of sleepiness. TSD are quite good at detecting the fact that they’re sleep deprived
But at 4/6hours they were not as good at detecting this
This has implications for sleep deprived drivers who think they’re fine
What was seen in stage 2 differences?
Those with less total sleep spent less time in stage 2, we naturally sacrifice this stage
What could be seen in deep sleep differences?
Very similar across groups, serves an important function and the body is reluctant to sacrifice this stage
What was seen in REM differences?
Had small reduction but not as significant as stage 2 reductions
What is the relevance of delta power?
Delta power is much greater when you’re sleep deprived - it is linked to SWS and process S
When you are sleep deprived, sleep pressure continues to build so you spend more time in deep sleep
How did Yoo et al. (2007) investigate SD and emotional well-being?
assigned individuals age 18-30 to either a sleep deprivation group (awake for 35 hours) or a control group (normal sleep)
Shown a series of stimuli, starting with +ve images and getting more and more -ve whilst also measuring fMRI responses
What was found from Yoo et al. (2007)
Both groups showed that the amygdala was activated when viewing the negative stimuli
The SD group activity of the amygdala was 60% greater than the control group - specifically in relation to negative images
What happens in the amygdala when you are sleep deprived?
It is over active, when you are asleep the amygdala is connected to the medial PFC which acts as brakes on the amygdala (controlling it)
When you are sleep deprived, there seems to be a disconnect between these 2 regions, so no longer have control and explains the increased activity
How can sleep affect weight management?
Can help with appetite control when get sufficient sleep
Even PSD can affect weight management
2 key hormones involved in regulating metabolism:
- leptin
- ghrelin
When you are sleep deprived there is a disruption in these hormones
What is Ghrelin?
a fast acting hormone produced in the cells of the stomach and increases the drive to eat
When you are sleep deprived there is an increase in ghrelin levels so an increased drive for high calorie food
What is Leptin?
Produced in white fat cells and suppresses the appetite, it tells us when we’re full
When you are sleep deprived there is a decrease in leptin so are reduced feelings of satiety
What is the combined effect of these 2 hormones?
Collectively increase appetite and increase food consumption
Linked to obesity
Sleep deprived bodies will hold onto all the fat and are more likely to lose muscle
What is the effect of SD on the immune system?
It is the same as putting your body under stress
It weakens the immune systems by reducing NK cell levels which are key for fighting off infections
If people are chronically sleep deprived then they will have chronically reduced NK cell levels
What are the effects of SD on neurodegeneration?
Beta-amyloid plaques are linked to Alzheimer’s disease.
Studies have found that poor sleep leads to a beta-amyloid build up.
Deep sleep usually clears toxins but without it they will present
This build up will eventually lead to neuronal death and synapse loss which is linked to Alzheimer’s and cognitive decline
