sleep and stress psych

Evolutionary purpose of sleep

Time for humans to hide from predators and conserve energy while the day was used for eating, drinking, and reproducing.

Restorative purpose of sleep

The claim that sleep restores the body's homeostasis which is disrupted during wakefulness.

Energy restoration during sleep

Sleep allows energy levels that decline during wakefulness to be restored.

Sleep-wake cycle

A recurring daily pattern of wakefulness and sleep measured by regular events like eating and sleeping.

Regulators of the sleep-wake cycle

Circadian rhythm, body temperature, metabolic rate, and hormone release including melatonin.

Circadian rhythm

The ~24-hour bodily cycle that controls the nocturnal release of hormones including melatonin.

Melatonin

The hormone that regulates the sleep-wake cycle.

Typical night's sleep cycles

Consists of 4 to 6 sleep cycles lasting approximately 90 minutes each, altering in length throughout the night.

The four sleep stages

NREM 1, NREM 2, NREM 3, and REM.

NREM 1 stage characteristics

Transition between wakefulness and sleep with decreased heart rate, slow rolling eye movement, and relaxed muscles. Lasts 1-7 minutes.

NREM 2 stage characteristics

Light non-REM sleep lasting 10-25 minutes, featuring slowed heart rate, stopped eye movement, and occasional muscle twitches.

NREM 2 cycle pattern

Increases in length with each repetition through the night.

NREM 3 stage characteristics

Deep non-REM sleep lasting 20-40 minutes with decreasing heart rate, minimal eye movement, and maximum muscle relaxation.

NREM 3 cycle pattern

Reduces in length over successive sleep cycles.

REM sleep characteristics

Stage where dreams occur, heart rate increases to match wakefulness, rapid eye movement happens, and muscles are temporarily paralyzed.

REM cycle duration pattern

Increases in duration over the night, ranging from a few minutes to an hour.

Acute sleep deprivation

A severe reduction or complete lack of sleep over a short period, typically less than 5 hours a night over 24 hours or consecutive nights.

Causes of acute sleep deprivation

Staying up late for an assignment, illness, jet lag, or stress.

Reversibility of acute sleep deprivation

Effects can be reversed with adequate sleep.

Effects of partial sleep deprivation on attention and mood

Increased lapses in attention, decreased mood, and increased irritability.

Physical and cognitive effects of partial sleep deprivation

Longer reaction times, blurry vision, and increased light sensitivity.

Chronic sleep deprivation

Inadequate sleep for more than a few weeks, sometimes lasting years, caused by issues like insomnia.

Reversibility of chronic sleep deprivation

Difficult to reverse.

Cardiovascular effects of chronic deprivation

Increased blood pressure and high cholesterol levels, which can lead to heart disease.

Metabolic and emotional effects of chronic deprivation

Increased intake of high-energy foods, risk of obesity, and negatively affected emotional regulation.

Sleep hygiene definition

Behavior and sleep environment that results in healthy sleep.

Screen time rule for sleep hygiene

Stop screen time at least one hour before bed because blue light stops melatonin production.

Consistent sleep pattern benefits

Important for regulating the circadian rhythm and improving sleep quality.

Environmental sleep hygiene rules

Keep the room free of distractions and use the bed for sleeping and intimacy only to create a cognitive link.

Aim of He Et Al (2020) study

To determine how phone use before bed affects mood, working memory, pre-sleep arousal, sleep quality, and sleep habits.

Participants in He Et Al (2020)

38 university students with poor sleep quality who used phones before bed.

PANAS in He Et Al (2020)

Self-report measure assessing positive and negative emotions over the past week using 20 statements and a 5-point Likert scale.

N-back task in He Et Al (2020)

A computer program used to test working memory by having participants respond to specific number sequences.

PSAS in He Et Al (2020)

A self-report Likert scale using 16 statements about cognitive arousal.

PSQI in He Et Al (2020)

A 19-item self-report measure assessing sleep quality and disturbances over the past month.

Variables in He Et Al (2020) study

Independent variable is mobile phone use 30 minutes before bed; dependent variable is the effect on sleep, mood, working memory, and pre-sleep arousal.

Procedure of He Et Al (2020) study

38 students randomly assigned to control or experimental groups (19 each); experimental group abstained from phones 30 minutes before bed for 4 weeks.

Findings of He Et Al (2020) study

Less time to fall asleep, slept longer, improved quality, reduced pre-sleep arousal, improved positive affect, reduced negative affect, and improved working memory.

Contributions of He Et Al (2020) study

A relatively recent study utilizing well-established measures that allow for replication and testing of reliability.

Criticisms of He Et Al (2020) study

Small sample size limits generalisability and only subjective data was collected, which could show bias.

Selye's definition of stress

Nonspecific response of the body to a psychological or physiological demand.

Distress

Negative stress response with physical reactivity and negative emotions.

Eustress

Positive stress response that motivates and enhances functioning.

Stressors

Sources of stress originating from internal or external factors.

Four categories of stressors

Social, cultural, environmental, and psychological.

Environmental stressors

Stressors arising from an individual's conditions and surroundings.

Psychological stressors

Stressors caused by emotional and cognitive factors.

Social stressors

Stressors stemming from relationships and interactions with society.

Cultural stressors

Stressors emerging from cultural identity, values, and norms.

Acute vs. chronic stressors

Stressors can be short-term (acute) or long-term (chronic).

General Adaptation Syndrome (GAS)

Selye's set of physical defenses reacting to harmful physical and psychological stimuli.

Three stages of GAS

Alarm, resistance, and exhaustion stages.

Alarm stage

Initial response where the amygdala signals the hypothalamus to trigger the SNS and adrenal glands.

Sympathetic Nervous System (SNS)

Branch of the ANS that prepares the body for increased activity during arousal.

Cortisol

Steroid hormone secreted by adrenal glands during stress.

Adrenaline

Hormone increasing heart rate and supporting glycogen-to-glucose conversion in the liver.

Noradrenaline

Hormone causing blood vessels to constrict, increasing blood pressure.

Resistance stage

Body repairs itself by reducing SNS activity and initiating the PNS.

Parasympathetic Nervous System (PNS)

Branch of the ANS that calms the body and maintains homeostasis.

Exhaustion stage

Prolonged stress depletes reserves, causing fatigue, reduced motivation, and health risks.

Social Readjustment Rating Scale (Holmes & Rahe, 1967)

Assesses stress from significant life changes using 43 common life events.

Life Change Units (LCU)

Scores estimating the level of response and adjustment required for life events.

Lazarus and Folkman's transactional model

Stress is a dynamic process where perception and cognitive appraisals determine coping.

Cognitive appraisal

Cognitive abilities used by individuals to assess a stressful environmental event.

Primary appraisal

Initial assessment to determine if a situation is a potential threat, challenge, or harm.

Secondary appraisal

Evaluation of available resources and coping options to manage a situation.

Emotion-focused coping

Managing emotional reactions to stress when resources are perceived as insufficient.

Problem-focused coping

Addressing the root cause of stress when resources to deal with it are available.

Maladaptive coping strategies

Harmful and unhealthy stress management that avoids problems and exacerbates adverse effects.

Adaptive coping strategies

Beneficial and productive methods of managing stress by facing and dealing with stressors.