Stress

Stress is the body's non-specific response to any demand placed on it — a necessary alarm system that becomes harmful when it never switches off.

Types of stress

• Acute stress — short-lived, caused by an immediate challenge or danger (e.g. exam, accident, interview).
• Chronic stress — continues for a long time, due to ongoing problems (e.g. financial problems, continuous workload).
• Eustress — positive stress that motivates and improves performance.
• Distress — negative or excessive stress that causes discomfort and reduces functioning.

A common misconception is that all stress is bad. Moderate, time-limited pressure (eustress) sharpens focus and performance, whereas unrelenting distress erodes health. Hans Selye, who coined the term "stress" in biology, first observed that diverse demands produced a similar bodily response.

Causes of stress

Academic pressure, work overload, financial problems, family problems, relationship difficulties, illness or injury, lack of sleep, major life changes, examination pressure, social problems, fear and uncertainty, poor time management, and environmental factors (noise, overcrowding). Thomas Holmes and Richard Rahe developed the Social Readjustment Rating Scale, ranking life events by how much readjustment they require — showing that even positive changes (marriage, a new job) can be stressful.

The stress response

When a stressful situation (stressor) occurs, the hypothalamus detects the threat, the sympathetic nervous system is activated, adrenaline is released from the adrenal glands, and heart rate, blood pressure and breathing increase — the body prepares for action (fight-or-flight). With prolonged stress, the HPA axis (hypothalamus–pituitary–adrenal axis) is activated, increasing the release of cortisol, a slower-acting hormone that mobilises glucose and sustains the response.

The fast and slow arms of the response travel different pathways.

Selye described a three-stage General Adaptation Syndrome:

1. Alarm — the body recognises the stressor and mobilises (the fight-or-flight surge).
2. Resistance — the body adapts and copes while resources are gradually depleted.
3. Exhaustion — reserves run out, leaving vulnerability to illness.

Selye's three stages trace the body from mobilisation to depletion.

Richard Lazarus added the cognitive appraisal view: stress depends first on primary appraisal ("Is this a threat?") and then secondary appraisal ("Can I cope with it?"). The same event can be threatening or manageable depending on these judgments — which is why reappraisal is central to coping and connects to Emotion [blocked].

Lazarus framed stress as a two-step appraisal of an event.

Physical effects

Increased heart rate and blood pressure, rapid breathing, muscle tension, headache, fatigue, sweating, sleep disturbance, stomach/digestive problems, changes in appetite, and reduced immunity (with prolonged stress).

Psychological effects

Anxiety, irritability, anger, restlessness, poor concentration, difficulty making decisions, memory problems, low motivation, mood changes, feeling overwhelmed, and difficulty sleeping. Prolonged stress also contributes to burnout and can worsen conditions covered in Psychological Disorders [blocked].

Coping strategies

Coping styles are often grouped into problem-focused (tackling the source) and emotion-focused (managing the feelings).

• Deep breathing — slow, controlled breathing reduces physical arousal.
• Progressive muscle relaxation — tense and relax muscle groups systematically.
• Meditation — improves attention and emotional regulation.
• Physical exercise — walking, running, stretching, yoga.
• Time management — schedule and prioritize.
• Adequate sleep — maintain a regular schedule.
• Social support — share problems with trusted people.

Stress and illness

Long-term or severe stress can contribute to poor health and worsen existing problems. It may be associated with hypertension, cardiovascular problems, digestive problems, headaches, and muscle/neck pain. Chronic cortisol elevation can suppress immune function, slow healing and increase vulnerability to infection.

Key takeaways

• Stress is the body's response to a perceived demand, not the demand itself; appraisal shapes the reaction.
• Acute, chronic, eustress and distress describe different durations and valences of stress.
• The fast sympathetic-adrenaline response (fight-or-flight) is followed by the slower HPA-axis cortisol pathway.
• Selye's General Adaptation Syndrome has three stages: alarm, resistance and exhaustion.
• Lazarus emphasised primary and secondary appraisal in determining whether we feel stressed.
• Coping can be problem-focused or emotion-focused; chronic stress is linked to cardiovascular, digestive and immune problems.

Sources & further reading

• Stress — American Psychological Association
• Stress effects on the body — APA
• 14.1 What Is Stress? — OpenStax Psychology 2e
• Stress and the General Adaptation Syndrome — PMC (NIH)
• General Adaptation Syndrome — APA Dictionary of Psychology