General Adaptation Syndrome and Stress Resistance

General Adaptation Syndrome

Introduction to General Adaptation Syndrome

General Adaptation Syndrome (GAS) is a model describing the set of physiological reactions experienced during stressful situations. Developed by Hans Selye in 1956, GAS explains how the body responds to various stressors and the outcomes of these responses. GAS identifies three distinct phases that the body goes through when exposed to stress.

Phases of General Adaptation Syndrome

• Alarm Phase: The body's immediate reaction to a stressor, activating the nervous system and mobilizing energy resources.

• Resistance Phase: The body attempts to adapt to the stressor. Physiological responses are sustained, and the body tries to cope with the stress.

• Exhaustion Phase: If the stress continues for a prolonged period, the body's resources become depleted, leading to decreased resistance and increased susceptibility to illness.

Stress Resistance

Stress resistance refers to the body's ability to adapt to and function under stress. The level of resistance varies across the three phases of GAS:

• Alarm Phase: Stress resistance is low as the body is initially shocked by the stressor.

• Resistance Phase: Stress resistance is high as the body adapts and copes with the stressor.

• Exhaustion Phase: Stress resistance drops as the body's resources are depleted.

Detailed Description of Each Phase

• Alarm Phase:

  • Mobilizes the sympathetic nervous system.

  • Prepares the body for "fight or flight" response.

  • Symptoms: Increased heart rate, heightened alertness.

• Resistance Phase:

  • Body attempts to maintain homeostasis.

  • Physiological responses continue to manage the stressor.

  • Stress hormones remain elevated.

  • The body is actively resisting the stress response.

• Exhaustion Phase:

  • Resources are depleted.

  • Physical wear on organs and tissues.

  • Symptoms: Hypertension, gastrointestinal issues, risk for diabetes, muscle tension/headaches, poor immune function.

  • Increased susceptibility to illness.

Graphical Representation of Stress Resistance

The following table summarizes the changes in stress resistance across the three phases:

Phase	Stress Resistance	Key Features
Alarm	Low	Initial shock, mobilization of resources
Resistance	High	Adaptation, coping mechanisms active
Exhaustion	Low	Resource depletion, increased illness risk

Examples and Applications

• Example 1: At the end of the semester, a student feels run down and suffers from regular tension headaches (Exhaustion Phase).

• Example 2: Starting a new job in a competitive company, a person is questioned about qualifications and feels pressure (Alarm Phase).

• Example 3: Working extra hours to meet deadlines, a person feels the demands but manages to perform well (Resistance Phase).

Susceptibility to Illness

• Individuals are most susceptible to illness during the Exhaustion Phase of general adaptation syndrome, as the body's resources are depleted and immune function is compromised.

Key Terms

• Stressors: Events or conditions that trigger the stress response.

• Homeostasis: The body's tendency to maintain internal stability.

• Sympathetic Nervous System: Part of the autonomic nervous system responsible for the "fight or flight" response.

Additional info: The General Adaptation Syndrome is foundational in understanding how chronic stress can lead to health problems, emphasizing the importance of stress management techniques in maintaining overall well-being.