November 25th : Lecture 22

Stress & Health

Lecture Overview

Stress

Effects of Stress

Perceived Control

Physiological Thriving

Reducing Stress

Stress

Stress is operationalised in two ways:

Psychological events causing stress

Physiological responses to stress

Psychological Stress

Degree to which people have to change and readjust their lives in response to an external event

Psychologically Stressful Events

Both “good” and “bad” things can cause significant stress

Physiological Stress

Stress on the body caused by physical or psychological stressors

Allostasis

Body’s ability to adapt to constantly changing environments to maintain homeostasis

Tight Allostatic System

One that moves from high to low levels of arousal flexibly and fluidly depending on demands

Allostatic Load

A chronically elevated state of arousal which damages the body and makes it less able to flexibly adapt to the environment

Result of chronic stressors

Associated with heart disease, diabetes, suppressed immunity, hypertension

Effects of Stress

Stress & Performance

Stress & Health

Stress & performance

When motivated to perform well, the way your body responds to the stressor can either IMPROVE or INHIBIT your performance

Improving Performance: Challenge

Inhibiting Performance: Threat

Challenge & ThreatChallenge Threat

Physiological

Patterns

↑ Heart Rate ↑ Heart Rate

↑ Strength of Heart Contraction

Mild-or-No increase in strength of Heart

Contraction

↑ Cardiac Output (Blood Circulating in Torso)

↓ Cardiac Output

↑ Diameter of Circulatory Vessels

↓ Diameter of Circulatory Vessels

Performance

Implications

↑ blood flow to brain ↓ blood flow to brain

↑ blood to effector muscles

↓ blood to effector muscles

↑ cognitive & physical performance

↓ cognitive & physical performance

Why Respond with Challenge or Threat?

What you expect is what you get …

… it all comes down to how you appraise the situation:

If you perceive that your ...

PersonalResourc

es

Situational

Demands

PersonalResourc

es

Situational

Demands> <

Challenge Threat

Cognitive Appraisals & Cardiovascular Responses

Tomaka, Blascovich, Kibler, & Ernst (1997)

Method:

1. Have participants complete verbal math task

2. Before task, asked participants:

Q1. How well can you can cope with the upcoming task?

Q2. How threatening is the upcoming task?

3. Divide participants into 2 groups:

Challenge Appraisals: Q1 > Q2

Threat Appraisals: Q1 < Q2

Cognitive Appraisals & Cardiovascular Responses

Tomaka, Blascovich, Kibler, & Ernst (1997)

Results: Cardiac Output by Cognitive Appraisals

Cognitive Appraisals & Cardiovascular Responses

Tomaka, Blascovich, Kibler, & Ernst (1997)

Results: Performance by Cognitive Appraisals

Extreme Stress & Memory

In response to extreme stressors, body releases catabolic hormone cortisol

Cortisol reduces memory and linguistic functioning

Cortisol & Cognitive Performance

Cortisol:

Decreases hippocampal mass in rats

Restricts blood flow in the hippocampus

Reduced linguistic complexity among humans giving speeches

Stress & Health

Stress & Immunity

Stress & Long-Term Health

Stress & Immunity

Psychological stress decreases immune functioning, making you more susceptible to disease

Cohen’s Hotel Study

Cohen, Tyrrell, & Smith (1991)

Method:

1. 420 healthy adults invited to stay a week in a hotel

2. Completed measures of life stress

3. Were exposed to common cold viruses through nasal spray

4. Monitored for 7 days post-exposure

Cohen’s Hotel Study

Cohen, Tyrrell, & Smith (1991)

Results:

Stress & Long-Term Health

Revisiting Allostatic Load …

Chronic stress predicts:

Hypertension

Type II Diabetes

Weakened immune system

Perceived Control

The belief that we can influence our environment in ways that determine whether we experience positive or negative outcomes

Self-Efficacy

The belief that you can competently complete the actions necessary to deal with a demanding situation

Learned Helplessness

The acquired sense that one can no longer control the environment, with the result that one gives up trying

Perceive negative events as:

Stable: Caused by factors that don’t change with time

Internal: Caused by you

Global: Causes of one negative event apply to other events

Learned Helplessness

Seligman & Maier (1967)

Method:

1. Phase 1: Two groups of dogs receive shocks while strapped in hammocks

Group A had control: Lever next to nose turned off shocks

Group B had no control: No lever to affect shocks, but same duration of shocks as Group A

2. Phase 2: Brought into divided pen (2 compartments, separated by short barrier)

Electrified floor of one compartment 10 seconds after a buzzer rings

If dog leaps to other compartment in less than 10 seconds, they won’t get shocked

Learned Helplessness

Seligman & Maier (1967)

Results: Time spent in first compartment after buzzer rang

Physiological Thriving

But sometimes …

Stress = Thriving

2 Aspects of “Positive” Stress:

Acute stressors (instead of chronic)

Complete relaxation in between stressors

Physiological Toughening

Fast and strong mobilization of bodily stress responses during a stressor coupled with rapid recovery after the stressor is the healthiest response

Physiological Toughening in Animals

Animals exposed to chronic stressors showed allostatic load

Animals exposed to intermittent stressors showed toughening

Increased immune response and suppression of cortisol

Physiological Toughening in Humans

Performance of Swedish students directly predicted by:

Strong hormonal response to an exam

Rapid return to baseline post-exam

Physiological Thriving

Epel, McEwen, & Ickovics (1998)

Compared to no stress or chronic stress, intermittent stressors lead to:

More effective coping with subsequent stressors

Healthier immune system

Longer cell life

Epel, McEwen, & Ickovics (1998)

Compared to no stress or chronic stress, intermittent stressors lead to:

Responding positively to past stressors leads to perception of benefiting from stressors

Viewing stressors as a challenge improves responses to subsequent stressors

Psychological Thriving

Taking Stock

The ability to recover from stressors can turn potentially damaging events into empowering ones

Appraisals of resources vs. demands affect your physiological ability to perform

If you feel threatened …

Boost your resources: Practice makes perfect!

Re-appraise the situational demands

Know that if you can go in with confidence, your body will back you up!

Challenge responses are positive responses to stressors => Physical Thriving & Resilience to Future Stressors

Reducing Stress

Exercise

Meditation

Exercise & Stress Reduction

Berger & Motl (2000) reviewed > 80 studies

Exercise reliably improves mood and reduces stress

Caveats:

Regularity: ≥ 3 x per week

Duration: ≥ 20 minutes per session

Intensity: ≥ moderate intensity (break a sweat)

Meditation

A class of techniques designed to influence an individual’s perception of consciousness through the regulation of attention

Benefits of Meditation

Benefits of meditative practice:

Improved immune functioning

Decreased stress, improved well-being

Decreased relapse of chronic depression

Faster recovery from disease

Increased left pre-frontal asymmetry

Left Pre-Frontal Cortex Asymmetry

Asymmetry in activity levels of left and right prefrontal cortex

The “Monk Experiments”

Left activity > 7 x right activity

More Generalizeable Populations: US Employees

Left Activity ≥ 1.5 x Right

Right Activity ≥ 1.5 x Left

• More positive emotion• Approach orientation• High immune functioning

• Greater incidence of mood disorders

• Avoidance orientation

Relaxation & Meditation

When to meditate?

Whenever you think of it!

Try meditating for 5 min./day for overall improvement

Relaxation techniques to deal with immediate stressors:

http://www.utsc.utoronto.ca/psyb10/documents/relaxation.pdf

Focusing on Breath

Given that:

Inhaling increases your heart rate, and

Exhaling decreases your heart rate

Exhale longer than you inhale to slow heart rate

What Doesn’t Kill You Makes you Stronger

Next time (Wednesday, 12/2):

Last Lecture!

Relevant Websites:

Toronto Meditation Guide:

http://torontomeditationguide.org/

CMHA Coping With Stress Info & Resources:

http://www.cmha.ca/english/coping_with_stress/