Stress & Health
November 25th : Lecture 22
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 & Threat
Physiological
Patterns
Challenge
Threat
↑ 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
↑ blood flow to brain
↓ blood flow to brain
Performance ↑ blood to effector muscles
Implications
↑ cognitive & physical
performance
↓ blood to effector muscles
↓ 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 ...
Personal
Situational
Resource >
Demands
s
Personal
Situational
Resource <
Demands
s
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 postexposure
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
Psychological Thriving
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
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
Left Activity ≥ 1.5 x Right
• More positive emotion
• Approach orientation
• High immune functioning
Right Activity ≥ 1.5 x Left
•
•
Greater incidence of mood
disorders
Avoidance orientation
The “Monk Experiments”
Left activity > 7 x right activity
More Generalizeable
Populations: US Employees
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_st
ress/