Ch.4: Stress

Eustress vs. Distress

Eustress: stress that stimulates person positively

Distress: stress that stimulates person negatively and disrupts normal functioning

Effects of Stress

Stress induces a physical response, exciting the nervous, endocrine, musculoskeletal system

• emotional + psychological conditions affect the body

• physiologic disorders influence one’s state of mind

Physical responses to stress: Acute and Chronic

Acute: response to intermittent stimuli, has varied intensity, and ends when threat is avoided

• HR increases, bronchodilation, increased focus, faster reaction time

Chronic: prolonged activation of stress response to perceived threat, no completion of stress cycle

• diminished immunity, cancer, heart disease, excess of free radicals, shortening telomeres

Selye’s Stress Response Theory

Stressor is any challenging demand on the body that illicits a response - can be positive/negative

Depends on person’s adaptive ability which allows one to maintain homeostasis depending on their coping mechanisms (based on how we perceive events from past experiences)

Involves neural, endocrine, immune response

• short term has protective effects

• long term creates diminished effectiveness

Selye’s General Adaptation Syndrome - ALARM stage

ALARM: activation of CNS, SNS, adrenal glands

• increased alertness, cardiorespiratory stimulation, pupil dilation, blood flow to muscles

• vasoconstricts blood vessels to bring blood to heart, lungs, muscles

• endocrine system activates

  • hypothalamus releases corticotropin releasing factor (CRF)

  • anterior pituitary releases adrenocorticotropic hormone (ACTH)

  • adrenal cortex releases cortisol

    • increased blood glucose for more energy

    • short term enhances immune response, but long term suppresses immune response

  • posterior pituitary releases antidiuretic hormone (ADH) to increase water and sodium reabsorption, increasing HR and BP

  • adrenal medulla releases epinephrine and norepinephrine

Selye’s General Adaptation Syndrome - RESISTANCE stage

Continued hormone and catecholamine (epi/norepi) release

• if stress goes away, PSNS induces relaxation

• if not, body’s response to stress lessens over time

Selye’s General Adaptation Syndrome - EXHAUSTION stage

Stress overwhelms the body, chronic stress adversely impacts overall health

• long term cortisol suppresses immune system

• increased risk for infection as WBC response decreases and thymus gland atrophies

McEwen’s Stress Response Theory

Allostasis: dynamic state of balance in response to stressor, as opposed to homeostasis

Frequent stressors change physiological balance and create a new setpoint (“new normal”)

EX: chronic stress leads to hypertension , a new higher setpoint for BP

Allostatic load

The wear and tear on body systems caused by stress

• due to the stressor AND individual’s ability to respond

accumulates due to repeated stressful experience, inability to adapt to stress, prolonged reaction to stressor

Allostatic overload

When stress exceeds body’s ability to adapt

• results in pathophysiological disorders

• lifestyle choices also play a role in adaptive capacities

  • obesity, sedentary lifestyle

  • EX: insulin resistance + excess fat add stress to body - result is diabetes as body has become overwhelmed

Common stress related disorders

asthma

atherosclerosis

autoimmune disease

cerebrovascular disease

CAD

diabetes

GAD

hypertension

IBS

migraine

Treatment for Stress: Lifestyle Practices

reduce caffeine intake

restorative sleep

social support

exercise

meditation/yoga

psychotherapy

Role of Serotonin and Tryptophan

Serotonin: neurotransmitter in brain and GI tract

• levels depleted during stress - leads to GI upset and indigestion/lack of feeling calm and relaxed

Tryptophan: amino acid, a precursor to serotonin

• eating carbs helps with tryptophan uptake in the brain, which had calming effects

• insulin helps uptake of other amino acids into muscles but tryptophan remains in circulation, allowing it to cross blood-brain barrier to form serotonin

Pharmacological Treatments to Reduce Stress

Sedatives: depress CNS, inducing relaxation (EX: downers, alcohol, Benadryl)

Antidepressants: modulate neurotransmitters in the brain

• takes 3 weeks to reach therapeutic levels

Benefit of Exercise

40 minutes, 3-4 days a week

weight control

Cardiovascular health: increased vasodilation, decreased fibrinogen (indicator of clots), angiogenesis, increased heart efficiency, decreased inflammation

GI system: assists peristalsis, decreases cancer risk

Psychological: stimulates neurotransmitter release, increased oxygen, endorphin release

Musculoskeletal system: increased muscle strength and size, metabolic rate, bone diameter and strength

Glucose tolerance: enhances glucose uptake

Effects of Immobiility

• Atelectasis: complete/partial collapse of lung

• bone demineralization

• decreased cardiac output, pulmonary function

  • EX: pulmonary embolism - clot travels into heart

• pressure ulcers

• depression

• decreased peristalsis, constipation

• increased susceptibility to aspiration (pneumonia)

• increased susceptibility to orthostatic hypotension: delay in arterial vasoconstriction (BP drops, HR rises)

• muscle atrophy

• gait and balance disturbance

• reduced cough effectiveness

• venous stasis, deep vein thrombosis: increases pressure, causes edema

Effects of Immobility in Joints and Muscles

No activity = joints assume flexion + contractures (fetal position)

Nurses MUST TURN IMMOBILE PTS (Q2 turns + protective padding + TED stockings for venous return) + passive ROM

Hip joint fractures common (trabecular bones go first)

Pathological fractures

Effects of immobility in Integumentary System

Pressure sores develop over bony prominences

With ulcers, wound care necessary as infection can extend into bloodstream (septicemia)

Decubitus ulcer stages:

1. redness

2. loss of epidermal/dermal layers

3. deep into dermis, reaching fat

4. loss of full thickness tissue, down to muscle/bone

Effects of Immobility: Psychosocial

Mood, orientation, cognitive abilities affected

Anxiety, depression, restlessness, fear, mood swings