General Adaptation Syndrome (GAS) (Selye-1936, 1983)

Physiological Response to Stress

• Accelerated heart rate

• Breathing rate increases

Alarm Stage

First stage: initial response to stressor, occurs 6-48 hours after detection.

Threat detected by amygdala sends signal to hypothalamus initiates sympathetic nervous system, blood stream sends signal to adrenal glands. signal stimulates release of cortisol, adrenaline and noradrenaline in adrenal glands → fight or flight response:

Sympathetic Nervous System

Branch of autonomic nervous system, regulates glands and internal organ function to physically prepare body for increased activity during heightened physical or emotional arousal

Hormones

chemical substances secreted into blood by endocrine glands to simulate function of organs

Cortisol

Steroid hormone secreted from adrenal glands when body experiences stress.

• enables continual blood sugar supply providing body energy to deal

• increases pain tolerance,

• reduces immune system performance, impairs cognitive ability

Adrenaline

Hormone secreted from adrenal glands, increases heart rate and supports conversion of glycogen into glucose in liver (Glyogenolysis)

Noradrenaline

Hormone/Neurotransmitter secreted from adrenal glands, cause vasoconstriction and increase blood pressure

Resistance Stage

Second Stage: body reduces activity to repair from initial shock through parasympathetic nervous system.

• adrenaline, noradrenaline, cortisol continue secretion

Parasympathetic Nervous System

Branch of autonomic nervous system, reverses functioning produced by Sympathetic system by calming body, maintaining energy level suitable for homeostasis

Exhaustion Stage (IE+CE)

Third stage: If stress continues unresolved, body’s mental and physical reserves deplete, limiting effectiveness of adrenal glands, decrease blood-sugar levels.

Immediate effects: fatigue, reduced motivation.

Chronic effects: depression, anxiety → weakens immune system possibly developing conditions

Limitations

• Oversimplification → universal stress response, not acknowledging individual differences in coping and resilience

• Limited scope→ focuses on physiological responses

• Lack of specificity → no differentiation between types of stressors and specific effects on body

Applications in field of Health and Wellness

• Stress management technique

• Promoting resilience

• Preventing stress-related illnesses