sleep + some stress

Sleep

State if partial or total loss of consciousness in which mental and physical activity are reduced

2 reasons why humans are motivated to sleep

Evolutionary

Restorative

Evolutionary purpose of sleep

Sleep serves a a means to increase an animals or humans chance of survival in its environment. Early humans used day time to eat, drink and reproduce. Dark at night time, increases risk of injury, threaten their survival. Hard to avoid predators at night. Energy conservation

Restorative purpose of sleep

Sleep allows us to recharge our bodies and recover from the physical and psychological work during the day. Sleep maintains homeostasis of the body. It allows for energy conservation, increased immunity, repairs and replenishes body, enhances mood, actives growths hormones

Sleep wake cycle

The recurring 24-hour pattern of sleep and wakefulness. Typically consists of 16 hr daytime wakefulness and 8 hr of night time sleep.

Circadian rhythm

A biological cycle that repeats approximately every 24 hrs.

What is the sleep wake cycle regulated by

Circadian rhythm, body temp, metabolic rate and release of hormones like melatonin and cortisol

Suprachiasmatic nucleus (SCN)

In the hypothalamus acts as the body’s master clock and responds to light cues from the environment

Melatonin

Hormone released by the pineal gland which increases in the evening. This helps promote sleepiness. It decreases in the morning to help support wakefulness

Cortisol

Hormone released by the adrenal gland. It peaks in the morning to help us wake up. It deceases at night to allow for rest

NREM

Repairs and restores the body. Consists of NREM 1 2 & 3. Increasing in the depth of sleep

REM

Repairs and restores the brain. Rapid eye movement and dreaming

Typical normative adult sleep cycle

4-6 hrs

Each cycle is 90-110 min

Each cycle will vary in length

Sleep latency

Time it takes to fall asleep

Sleep cycle stages

1. NREM 1

2. NREM 2

3. NREM 3

4. REM

NREM 1 Summary

Lightest stage of sleep. Transitional stage between wakefulness and sleep.

Heart rate begins to slow down and may show minor fluctuations.

Eyes slowly rolling movement, once asleep stop moving.

Muscles start to relax and tension decreases, hypnic jerks may occur.

Alpha waves change to theta waves

NREM 2 Summary

Light sleep

Heart rates becomes more regular and slower

Eye movement stops

Muscle tensions continues to decline, occasional minor twitches.

Theta waves, along with sleep spindles and k-complex’s

NREM 3 Summary

Deep sleep

Heart rate is steady and at its slowest

No eye movement

Muscle tension is at its lowest

Predominately delta waves

REM Summary

Vivid and memorable dreams

Heart rate is irregular and may increase, sometime reaching levels similar to wakefulness

Eye movement is rapid and jerky

Muscle tension is virtually absent and they are temporarily paralysed (atonia), except for muscles involving breathing and eye movement

Beta like waves that include sawtooth waves

Sleep deprivation

The condition of not getting enough sufficient sleep

4 causes of sleep deprivation

1. Shift work

2. Drugs

3. Sleep environment

4. Stressors

Shift work

Impacts hues of sleep due to sleeping during the day and being awake at night. Hormones that are secreted (melatonin and cortisol) will be impacted reducing both quality and duration of sleep. Directed by light

Drugs

Can impact the progression of sleep stages, reducing both REM and NREM

Caffeine

Stimulant drug that delays onset of sleep

Alcohol

Depressant drug that causes night time awakenings and reduces REM sleep. Can relax muscles throughout body including throat = increase snoring and sleep apnoea, reducing sleep quality

Sleep environment

Light can cause interruptions to melatonin production. This prolongs falling asleep and reduces sleep quality.

Environmental noise can cause awakenings and reduce sleep quality.

Temperature and air quality can also play a role in the quality of sleep

Stressors

If an individual is dealing with stressor they are likely to experience difficulty falling asleep and anxiety. Anxiety can increase the difficulty falling asleep, this becomes a cycle. Increases sleep latency

Acute sleep deprivation

Severe reduction or complete lack of sleep over a short period. Generally 5 hrs of sleep over 24 hr period. Effects can be reversed with adequate sleep

Acute sleep deprivation causes

Staying up late to finish an assignment. Jet lag. Pulling an all nighter. Stree

Chronic sleep deprivation

The persistent reduction of sleep over a long period of time. Inadequate sleep for more than a few weeks at a time, sometimes lasting years

Chronic sleep deprivation causes

Insomnia. Work hours. Sleep disturbances. Lifestyle choices

Effects of acute sleep deprivation

Attention

Mood

Reflex speed

Vision

Attention as an effect

Reduces overall attention and increases the lapses of attention, where focus is temporarily lost

Mood as an effect

Can be significantly altered by sleep deprivation, reducing positive emotions and increasing negative emotional responses to stressors

Reflex speed as an effect

Slows reflex speed, leading to longer reaction times and delayed responses to stimuli

Vision as an effect

Becomes blurry, eye twitches (spasms) may occur and eyes become more sensitive to light

Effects of chronic sleep deprivation

Heart disease

Obesity

Insomnia

Anxiety

Heart disease as an effect

Increased blood pressure and high cholesterol levels are common side effects of chronic sleep deprivation, both of which lead to heart disease

Obesity as an effect

Can lead to individuals increasing their intake of high energy food as well as the overall amount of food they eat

Insomnia as an effect

A sleep disorder characterised by difficulties falling asleep or difficulties staying asleep (low sleep latency). It is also common to wake up not feeling well rested

Anxiety as an effect

Emotional regulation is negatively affected by chronic sleep deprivation, and this can exacerbate symptoms of anxiety.

Sleep hygiene

The behaviour and sleep environment that contributes to healthy sleep

3 techniques to improve sleep hygiene

Management of electronic devices

Consistent sleep pattern

Creation of a healthy sleep environment

Management of electronic devices

They emit blue light which inhibits melatonin production disrupting the circadian rhythm and making it difficult to fall asleep.

No electronic devices an hr before bed time is recommended.

Brain stimulation results from electronic device use increases sleep latency which reduces overall duration and/or quality of sleep

Consistent sleep pattern

Regulates our circadian rhythm. Increases sleep duration, decreases sleep deprivation. Flow guide for sleep hrs

Creation of a healthy sleep environment

Circadian rhythms can be disrupted by an uncomfortable sleeping environment.

It is recommended to sleep in a dark, quiet, cool and free from distractions room.

Bed should be for sleep and intimacy only

Air flow and good ventilation

Temp 16 to 20 degree, need low temp for NREM 3

Restricting bedtime mobile phone use: aim

To determine how limiting the use of mobile phones before bedtime affects mood, working memory, pre-sleep arousal, sleep quality and sleep habits

Restricting bedtime mobile phone use: participatnts

38 university students from the second military medical university (China) They had the habit of using their mobile phone before bed and poor sleep quality

Restricting bedtime mobile phone use: materials

Positive and negative affect schedule (PANSAS), N-bad test, pre sleep arousal (PSAS), Pittsbough sleep quality index (PSQI) and an online diary

PANSAS, PSAS, PSQI = Likert scale

N-back task = memory

Diary = self report

Restricting bedtime mobile phone use: design

IV= The use of mobile phones during bedtime versus no mobile phone for 30 min before bedtime

DV= Mood, working memory, pre-sleep arousal, sleep quality and sleep

habits

Restricting bedtime mobile phone use: procedure

1. Researchers obtained approval from ethics committee. Student volunteered by an ad on social media. Informed consent obtained

2. All participants completed the tests to measure DV’s

3. Participants were randomly assigned to experimental or control group (19 each)

4. For next 4 weeks participants in experimental group obtained from using mobile phone 30 min before bedtime. Control group continued to use phone as normal

5. At 4 week mark, all participants completed same texts again, and results were compared

Restricting bedtime mobile phone use: key findings

Participants who avoided mobile phone use for 30 minutes before bedtime fell asleep faster (reduced sleep latency), slept for longer, experienced better sleep quality, reported lower pre-sleep arousal, greater positive affect, less negative affect and showed improvement with working memory

Results of sleep quality measured using the PSQI at pre-test and after 4 weeks is shown with lower PSQI score indicating better sleep quality

Restricting bedtime mobile phone use: contributions to psych

Recent study that uses well established measure, allowing it to be replicated by other researcher. With replication comes the ability to assess reliability

Restricting bedtime mobile phone use: criticisms and limitations

Sample size was small, limiting the ability to generalise results to population that the sample was taken from

4 week intervention period was too short, limited the examination of long-term effects

All measures, except for n-back test, gathered subjective data from participants as they included self-reports measures and online diary entries

Subjective measures should ideally be used in combination with physiological measures as these collect objective data that is likely to be less biased

Stress Selye 1983

Is the non-specific response of the body to any physiological or psychological demand. To experience stress there has to be a stressor. When a person perceives that the demand of the stressor exceed their ability to cope then they will experience stress

2 types of stress

Distress

Eustress

Distress

Negative stress response typically accompanied by physiological reactivity and negative emotions.

Impedes our ability to perform at an optimum level

Often associated with maladaptive coping, leads to health risks

Eustress

Positive stress response that motivates and enhances functioning.

Individual feels stressed yet prepared to complete a task or deal with a situation

Stressor

Any person, object or event that challenges or threaten them, thus causing feeling of stress. Internal or external

4 types of stressors

Environmental

Psychological

Social

Cultural

Environmental stressors

The conditions and physical surrounding of an individual eg. noise, temperature

Psychological stressor

Caused by emotional and cognitive factors eg. conflict with parent

Social stressors

Relationships and interactions with society eg. peer pressure

Cultural stressors

Aspects of cultural identity, values and norms eg. discrimination

Characteristics of stressors

Source

Duration

Intensity

Source of stressors internal

Originate within the individual. Most common cause of stress. Thoughts, emotions and personal attitudes that create tension or worry

Source of stressors external

Pressures and challenges that come from the environment around us

Duration of stressors

Short term = acute, long term = chronic (more than a few weeks)

Intensity of stressor

Mild to severely distressing. The ability to cope depend on the intensity of the stressor

General adaption syndrome (GAS) Selye 1936, 1983

3 stage model that describes the body’s physiological response to prolonged stress.

1. Alarm reaction stage

2. Resistance stage

3. Exhaustion stage

Physiological response to stress

Increased heart rate and breathing rate

General adaption syndrome (GAS) Selye 1936, 1983 Alarm reaction stage

The body’s immediate response to a stressor

Consists of a shock phase, where physiological activity temporarily decreases followed by a countershock phase

During the countershock phase, the sympathetic nervous system activates fight or flight response, causing the release of the stress hormones such as adrenaline, noradrenaline and cortisol

General adaption syndrome (GAS) Selye 1936, 1983 resistance stage

The body attempted to cope with and adapt to the ongoing stressor

Physiological arousal decreases from its peak but remains above normal levels

The parasympathetic nervous system works to restore balance, while stress hormones continues to be released

General adaption syndrome (GAS) Selye 1936, 1983 exhaustion stage

Occurs when a stressor continues for a prolonged period and the body’s resources become depleted

The ability to cope decreases, increasing vulnerability to illness

Common effects include fatigue, reduced motivation, weakened immune functioning, anxiety, depression, and increased risk pf physical health problems