Defining stress

Stress represents the body's natural reaction to situations where we perceive demands or threats that challenge our ability to cope. It arises when we feel under pressure.

This concept can be viewed in different ways, building on ideas from researchers like Sarafino (2006). First, stress might be seen as the impact that external environments have on individuals, such as demanding situations that trigger discomfort. Second, it can refer to the physical changes in the body that occur in response to these events, like increased heart rate. Third, stress often involves an interaction between the person and their surroundings, where individuals actively choose how to respond using a mix of behaviours, thoughts, and emotions.

Physiology of stress

The body's response to stress follows a structured pattern, particularly when the stress is prolonged. This is captured in the General Adaptation Syndrome (GAS), a model proposed by Selye (1936). GAS describes how the body reacts and adapts to ongoing stressors through three distinct stages.

Stage 1: Alarm

This initial stage prepares the body for immediate action, often called the 'fight or flight' response. When a stressor is detected, hormones like cortisol, epinephrine (also known as adrenaline), and norepinephrine (also known as noradrenaline) maintain high arousal levels.

Stage 2: Resistance

If the stressor persists, the body enters a phase of adaptation. It attempts to cope by sustaining elevated hormone levels, which resist the return to normal states. Outwardly, the person might appear fine, showing no obvious signs of distress. However, this prolonged effort makes the body more vulnerable to illnesses.

Stage 3: Exhaustion

Eventually, the body cannot sustain this resistance indefinitely. This leads to fatigue and weakening of the immune system. This can result in physical damage and increases the risk of diseases.

Effects of stress on health

Stress influences health differently depending on its duration. Acute stress is short-term and often linked to immediate threats, while chronic stress is long-lasting and ongoing. These can affect various body systems, sometimes protectively and other times harmfully.

Acute stress and its protective role

In brief bursts, stress can enhance health responses. For instance, during events like surgery or receiving a vaccination, the body's acute stress reaction activates the immune system, boosting its efficiency to aid healing or fight infection.

Chronic stress and its negative impacts

When stress becomes chronic, it disrupts normal bodily functions across multiple systems. This happens because sustained high levels of hormones like cortisol suppress immunity and cause wear and tear.

Effects on the digestive system:

• Chronic stress alters hormone balances, increasing stomach acid production, which can contribute to ulcers.
• Behavioural responses to stress, such as smoking, excessive drinking, using non-steroidal anti-inflammatory drugs (NSAIDs like ibuprofen), or poor sleep, further heighten this risk.

Effects on the circulatory system:

• Persistent elevation in heart rate strains blood vessels and the heart.
• It raises blood pressure (hypertension), increasing the risk of coronary heart disease (CHD).
• High cholesterol can build up, leading to clots and narrowed arteries.
• Stress-related behaviours like overeating, alcohol consumption, and smoking compound these CHD risks.

Effects on the immune system:

• Chronic stress causes immunosuppression (weakening of the immune response), primarily due to elevated cortisol levels.
• For example, natural killer (NK) cells, which are white blood cells that attack infected or abnormal cells, decrease during prolonged stress, making the body more susceptible to illnesses.

Causes of stress

Stress can stem from various sources in daily life, often linked to significant changes or ongoing pressures. These causes interact with personal factors, influencing how intensely stress is experienced.

Life events as stressors

Major changes, even positive ones, can trigger stress. Holmes and Rahe (1967) developed the Social Readjustment Rating Scale (SRRS), a tool that assesses stress by scoring 43 life events (like marriage, job loss, or moving house) experienced in the past 12 months. Higher scores indicate more events, correlating with greater stress and increased illness risk. This shows that accumulating changes, regardless of whether they are good or bad, heightens vulnerability to health issues.

Work-related stress

Jobs can induce stress through specific demands or lacks.

Research highlights three key factors contributing to work-related stress:

• Under-stimulation - Repetitive, monotonous tasks lead to boredom and elevated stress hormones.
• High workload - Excessive responsibility and demands increase absence due to illness.
• Low control - Limited autonomy in tasks correlates with higher CHD rates, especially in roles with less decision-making power.

Key research studies on stress and health

Several studies provide evidence for how stress affects health, often focusing on physiological markers or long-term outcomes. These use methods like questionnaires and biological measurements to link stress to conditions like CHD.

Kiecolt-Glaser et al. (1984) on immune suppression

• Aim - This study examined how exam stress impacts the immune system in students.
• Participants - American medical students.
• Method - Blood samples were taken a month before exams (low stress) and during exams (high stress) to measure NK cell levels. Participants also reported on loneliness and stressful life events via questionnaires.
• Results - NK cell levels were lower during exams, with even greater reductions in those experiencing loneliness or additional stressors.
• Conclusions - Short-term stress suppresses immune function, increasing vulnerability to illness.
• Limitations - The sample was specific to students, potentially limiting generalisability.

Johansson et al. (1978) on work stress

• Aim - This research compared stress in different job roles at a Swedish sawmill.
• Participants - Finishers (repetitive, high-responsibility work) and cleaners (varied, lower-demand tasks).
• Method - Measured stress hormones and tracked illness/absence rates.
• Results - Finishers showed higher hormone levels, more illness, and greater absence than cleaners.
• Conclusions - Under-stimulation and high workload contribute to chronic stress and health issues.

Marmot et al. (1997) on job control and health

• Aim - This study explored work factors in UK civil servants.
• Participants - 10,000 civil servants.
• Method - Assessed workload, control, and CHD incidence over time.
• Results - No link between workload and stress, but low control correlated with higher CHD in lower-grade roles.
• Conclusions - Lack of job control is a key stressor leading to health problems.

Chandola et al. (2008) on work stress and CHD

• Aim - This longitudinal study investigated links between job stress and heart disease.
• Participants - 10,308 London-based civil servants aged 35–66.
• Method - Used the Job Strain Questionnaire for self-reported stress and isolation; tracked CHD incidents, cortisol levels (measured on waking and 30 minutes later), and behaviours like alcohol use, smoking, and exercise over 17 years, ending with clinical exams.
• Results - Work stress was lower in higher grades; it correlated with CHD in younger participants, poor health behaviours, and elevated morning cortisol later in the study.
• Conclusions - Chronic work stress raises CHD risk, with about 32% explained by unhealthy behaviours.
• Limitations - Relied on self-reports, which may introduce bias.

Friedman and Rosenman (1974) on Type A personality

• Aim - This research identified personality traits linked to CHD risk.
• Participants - Initially male CHD patients in the USA; later, 3,154 healthy men aged 39–59 followed for 8.5 years.
• Method - Compared CHD rates in patients versus spouses with similar diets; used questionnaires to classify Type A (competitive, ambitious, time-conscious, aggressive) versus Type B (relaxed) personalities.
• Results - Spouses had lower CHD; Type A men developed CHD nearly twice as often as Type B.
• Conclusions - Type A traits increase CHD risk, especially in white, middle-class men, by associating with higher cholesterol and faster blood clotting.
• Limitations - Focused on specific demographics, potentially overlooking other groups.

Evaluation of stress research

Research on stress has both strengths and weaknesses, which help assess its reliability and applicability.

Issues and debates in stress research

Stress explanations raise broader psychological questions about how we understand human responses.

Reductionism versus holism

Approaches like biological explanations (e.g., GAS), the SRRS, or Type A/B personalities can be reductionist, simplifying complex behaviours to single factors like hormones or scores. For example, labelling someone as purely Type A ignores contextual variations, as many people show mixed traits depending on situations. A holistic view, considering interactions between biology, environment, and personal choices, might better capture how situational factors shape stress reactions.

Cultural differences

Much research on work stress, such as studies by Johansson et al. (1978) and Marmot et al. (1997), was conducted in Western, individualist cultures where repetitive or low-control jobs are seen as highly stressful. In other cultures, these roles might be viewed differently, perhaps as stable or communal, affecting stress levels. This highlights the need for cross-cultural studies to avoid ethnocentric biases.