Sleep and sleep deprivation

Question 1

What is sleep in a physiological sense?

Answer 1

A period of reduced activity, associated with a typical posture and a decreased responsiveness to external stimuli. It is easy to reverse and shows physiological changes.

Question 2

How many Australian adults don’t get enough sleep regularly?

Answer 2

~7.4 million Australian adults

Question 3

How many deaths were estimated in 2016-17 due to lack of sleep?

Answer 3

3017

Question 4

What are the stages of a sleep cycle? (+Diagram)

Answer 4

Awake REM sleep nREM stage 1 nREM stage 2 nREM stage 3

Question 5

What defines the 2 types of sleep?

Answer 5

Eye movement and electrical patterns in a sleeping person’s brain

Question 6

What are the distinct stages of nREM sleep?

Answer 6

N1: Lasts 1 - 7 minutes and is defined by a low voltage, mixed-frequency pattern. N2: Forms spindles in the EEG recording and lasts 10 to 25 minutes. N3: Higher amplitude EEG waves and slow -wave activity and generally lasts 20 - 40 minutes.

Question 7

What happens to depth of sleep when progressing from N1 to N3?

Answer 7

The sleep becomes deeper and brain becomes less responsive to external stimuli and it becomes increasingly difficult to awaken an individual from sleep.

Question 8

What percentage of sleep is REM?

Answer 8

20 to 25% of total sleep in typical healthy adults.

Question 9

What does REM sleep EEG look like?

Answer 9

low-amplitude, high frequency waves and alpha rhythm

Question 10

What are the characteristics of REM sleep?

Answer 10

Rapid eye movements. Muscles in arms and legs are paralysed (could be a neurological barrier to acting out dreams) Visually intense dreams Hard to awaken, heart rate and BP also increased, core temperature not well regulated and sexual arousal is common.

Question 11

When do night terrors typically occur?

Answer 11

nREM sleep

Question 12

When does dreaming occur most often?

Answer 12

Both REM and nREM

Question 13

What are the theories on why we sleep?

Answer 13

Adaptive theory of sleep (inactivity is adaptive to keep away from danger) Theory of energy conservation (Helps us conserve energy and reduce expenditure when less productive) Restoration theory of sleep (Repair of injuries such as muscle growth, tissue repair, protein synthesis, and growth hormone, deficiency in growth hormone causes aches, and symptoms similar to depression) Information consolidation theory of sleep (Sleep is correlated with brain plasticity. Sleep is important for memory consolidation particularly during REM sleep)

Question 14

What restorative mechanisms are active during sleep?

Answer 14

Growth hormone production Physical restoration (kidneys replenish salt stores, brain and muscles replenish sugar and fat stores) Cognitive functional restoration (Neurons in the brain produce adenosine. Adenosine buildup = tired feeling)

Question 15

What stage of sleep is important for growth hormone production?

Answer 15

N3

Question 16

What are the characteristic changes to brain activity during sleep cycle?

Answer 16

Decrease in activation rate of most neurons from wakefulness to non-REM sleep. Patterns of neuron firing change from random and variable activity pattern during wakefulness to a more coordinated and synchronous pattern during non-REM sleep.

Question 17

What happens to body temperature during sleep cycle?

Answer 17

Reduced during non-REM sleep and during REM falls to the lowest point.

Question 18

What happens to respiratory changes during sleep cycle?

Answer 18

Breathing rate is irregular in both wakefulness and REM sleep and increases. Rate decreases and becomes more regular in nREM sleep.

Question 19

What happens to cardiovascular activity during the sleep cycle?

Answer 19

Non-REM overall reduction in heart rate and blood pressure. REM sleep more pronounced variation with changes cardiovascular activity and increases in heart rate and blood pressure.

Question 20

What overall physiological changes happen during sleep?

Answer 20

increased production of growth hormone in non-REM sleep. Physiological activities like digestion, cell repair, and growth are greatest during sleep.

Question 21

Why is sleep important for cognitive functions and memories?

Answer 21

During our sleep the brain processes information, consolidates memories, and enables us to learn and function effectively during daytime. Sleep is important for reorganising memories and producing insight and creative ideas from those memories. Sleep affects ability to use language, sustain attention, understand what we are reading and summarise what we are hearing.

Question 22

What percentage of Australian adults suffer from sleep deprivation?

Answer 22

33 - 45%

Question 23

What is the average reported sleep time?

Answer 23

7 hours (12%< 5.5 hours and 8% > 9 hours)

Question 24

What are the general symptoms of sleep problems?

Answer 24

Performance decrease: academic, physical, etc Behavioural difficulties Irritability Hyperactivity Frequent illness Headaches, jaw pain, earaches Daytime sleepiness Depression, anxiety

Question 25

What causes sleep deprivation?

Answer 25

Personal choice (Watch TV, socializing) Attitude (Much sleep is not needed) Work Illness Sleep disorders Poor sleep behaviours Environment Distress/anxiety Ageing

Question 26

What are the short term consequences of sleep deprivation?

Answer 26

Decreased performance and alertness Memory and cognitive impairment Stress relationships Poor quality of life Occupational injury Automobile injury

Question 27

Long term consequences of sleep deprivation:

Answer 27

High BP Heart attack Stroke Obesity Psychiatric problems Mental impairment Childhood growth retardation Injury from accidents Poor quality of life Immune function reduction Increased inflammation

Question 28

What mental illnesses are associated with sleep deprivation?

Answer 28

Anxiety Depression ADHD