Stress

Definition

  • Stress: A state of worry or mental tension, a response from the human body when put in difficult or overwhelming situations (WHO).

How the Body Responds to Stress

  1. Stressful event → signal travels to the amygdala.

  2. Amygdala interprets threats and alerts the hypothalamus.

  3. Hypothalamus activates fight or flight response.

  4. Adrenal glands release adrenaline.

Short term:

  • Causes heart rate and blood pressure increase.

  • Increase in breath rate and oxygen intake.

  • Blood flow diverted to muscle and brain.

Long term:

  • Cortisol released keeps body alert and maintains energy.

  • Causes high blood pressure, metabolic and digestive issues, reproductive issues.

  • Suppresses immune system.

  • Associated with anxiety, depression, impaired memory and concentration.

Stress Indicators

Emotional

  • Irritability

  • Mood swings

  • Anxiety

  • Feeling overwhelmed

Physical

  • Headaches

  • Muscle tension

  • Fatigue

  • Trouble sleeping

Cognitive

  • Difficulty concentrating

  • Racing thoughts

  • Forgetfulness

Behavioral

  • Changes in eating/sleeping habits

  • Social withdrawal

  • Procrastination

Common Sources of Stress

  • Academic pressure

  • Financial struggle

  • Relationships

  • Family expectations

  • Work + school balance

Biological/Psychological Causes

  • Fight or flight response

    • 3 stages: alarm → resistance → exhaustion

  • Chronic stress = burnout & anxiety

Culture & Family Stress

  • Cultural pressure & discrimination

  • Family stress spreads through relationships

  • Stronger in minority or immigrant households

Symptoms of Stress

Psychological

  • Depression, lack of caring, unproductivity

  • Irritability, anger

  • Boredom, low energy state, fatigue

  • Feeling overwhelmed or overburdened

  • Anxious/worried

  • Behavioral problems (gambling, smoking, etc.)

Physical

  • Muscle tension & pain, headaches, migraines

  • Shaking, trembling, spasms

  • Digestion issues

  • Stress eating

  • Sleep problems

  • Excessive sweating

  • Heart problems

  • Difficulty breathing, chest pain, deep breaths

  • High blood pressure

Short Term Stress

  • The body’s immediate response to a threat or challenge.

Causes:

  • Hyperventilation

  • Heart beats faster, increased blood pressure

  • Fight or flight

  • Liver produces more glucose to give body more energy

Long Term Stress

  • When stressors persist over extended periods without getting resolved or released.

Can lead to:

  • Cardiovascular disease

  • Digestive issues

  • Mental health conditions

  • Increased risk of heart and blood pressure problems

  • Weakens immune system

Physical Health Effects of Stress

  • Weakened immune system

  • Heart & circulatory problems (increase in heart rate & blood pressure)

  • Muscle tension & pain

  • Sleep disruption

  • Long-term health risks:

    • Obesity, diabetes, digestive issues, hormone & metabolism disruption

  • Can shorten overall lifespan and decrease quality of life

Mental & Emotional Effects of Stress

  • Anxiety & depression

  • Difficulty focusing & remembering things

  • Memory formation & recall issues

  • Irritability & mood swings

  • Feeling overwhelmed or burned out

Behavioral Consequences

  • Unhealthy coping habits (overreacting, smoking, drinking, etc.)

  • Social withdrawal & motivation loss

  • Poor decision making (making more mistakes, impulsive decisions)

  • Constant worry & fatigue

  • Reduced empathy & communication

  • More conflicts & less patience

  • Strained relationships

Academic Work & Performance

  • Trouble concentrating on tasks

  • Missed deadlines & lower grades

  • Increased absenteeism

  • Risk of burnout & quitting

Types of Stress

Acute / Key Stress

  • Short-term stress (minutes to hours)

  • Can be good for immune system short term as it boosts performance for a short while

  • Activates fight/flight

  • Prepares body to respond immediately

  • Brain uses it for physical & mental performance enhancement

Chronic Stress

  • Long-term stress

  • Disrupts hormones, weakens immune system & causes health problems

  • Overload of cortisol disrupts health systems over time

  • Impairs focus, reduces performance

  • Can cause mental issues (e.g., anxiety/depression)

  • Built up over time: “survival-based coping”

  • Maladaptive coping

  • Prepares body for extreme stressors

Cortisol

  • Cortisol acts as a biomarker (measurable indicator) of stress.

  • Hormone produced by adrenal glands in response to a stressful event.

  • Starts off the body’s physical responses to stress.

  • Chronic stress disrupts the HPA axis, affecting cortisol & melatonin levels.

  • Cortisol & melatonin are inversely related (one goes down, the other goes up).

Limitations of Perceived Stress Scales & Surveys

  • Subjectivity & response bias (influenced by mood, personality, emotion, etc.)

  • Memory errors (distorted by recent experiences or selective memory)

  • Cultural/language differences (cultural norms affect responses)

  • Stress fluctuates throughout the day, surveys only capture a snapshot

Catecholamines

  • Group of neurotransmitters & hormones produced mainly by adrenal glands & nervous system
    (e.g., epinephrine/adrenaline, norepinephrine, dopamine)

  • Reflect how stressed one's nervous system is

  • 8-OHdG (8-hydroxy-2-deoxyguanosine): molecular marker created when DNA is damaged by oxidative stress → shows oxidative injury

Endocrine System

  • Body’s primary system for long-term communication

  • Fundamental role: maintain constant internal environment

Disruptors:

  • Bisphenol A (BPA) disrupts endocrine functionality

    • Can increase risk of metabolic disorders

  • Hormonal imbalance increases likelihood of stress-related behavioral changes

Cortisol Measurement (Immunoassay Methods)

  • Blood cortisol: reflects cortisol at a specific moment (short), considered gold standard

  • Urinal cortisol: 24-hr collection, excessive fluid affects results

  • Salivary cortisol:

    • Easy, noninvasive

    • Can monitor treatment

    • Measures psychological stress

    • Late night testing can detect Cushing’s Syndrome

  • Hair cortisol:

    • Hair close to scalp sent to lab

    • Measures up to ~6 months of cortisol storage

Neurobiology & Stress

  • Prolonged chronic stress can cause development of Alzheimer’s

  • Stress triggers adaptive responses in organisms during survival

    • Leads to evolutionary changes through natural selection

Eustress (Good Stress)

  • Short-term & manageable

  • Motivates & strengthens body

  • HPA axis converts stress into productivity

    • Turns psychological stressors into physical ones

    • Enhances energy

  • Moderate stress activates brain systems

    • Increases memory & adaptation through HPA axis

Music & Stress

  • Different music genres significantly affect stress; silence causes minimal change

  • Effects depend on:

    • Tempo

    • Familiarity

    • Emotional association

  • Certain frequencies reduce stress or influence cognition (e.g., 480 Hz)

Animal Interaction & Stress

  • Increases oxytocin (emotional bonding hormone)

  • Lowers cortisol, blood pressure & heart rate

AAT (Animal Assisted Therapy):

  • Used to aid treatment for anxiety, trauma, emotional stress

  • Mostly used in hospitals & nursing homes or similar settings

Sleep & Stress

  • Sleep clears stress hormones, balances amygdala, regulates cortisol levels

  • Strengthens prefrontal cortex (focus, decision-making, emotional control)

Lack of sleep:

  • Cortisol rises before stressful events

  • Amygdala overreacts

  • Increases body’s stress response

  • Weakens prefrontal cortex

Oversleeping:

  • Cortisol level drops too low → grogginess