Stress and (un)Healthy Aging

Martin Sliwinski

Penn State University

What is aging?

Aging: the accumulation of changes in an organism over time

Risk Mechanisms & Regulators (behavioral, biological & social)

Time-scales (linking short-term & long-term changes)

Aging often involves the study of involution (vs. growth/development)

Stress and (un)Healthy Aging

Memory Executive function

Cognitive Health Physical Health Emotional Health

Metabolic disorder Cardiovascular disease

Depression Anxiety

“Stress”

The Important Question(s)…

What connects stress exposure to health outcomes?

Health Emotional

Cognitive

Physical

Exposure

Event/

Hazard ?

What are critical periods in adulthood for intervention (normative/age-graded vs. nonnormative)

What is stress?

Physiological/Behavioral

Responses

Negative Emotional Response

Stress Response

(psychophysiological

sequelae)

What is stress?

Benign

Appraisal

Perceived

Stress “Subjective Stress” (experiential state)

Appraisal of Demand & Capacity

Environmental Challenge Stressor/Hazard (exposure)

Cohen, S., Kessler, R. C., & Underwood Gordon, L. (Eds.) (1995). Measuring

stress: A guide for health and social scientists. New York: Oxford.

What Makes Stress Bad?

Stress is not the culprit, chronic stress is!

Chronic Stress Persistent experience of negative emotional states

Allostatic Load: “Wear and Tear”

“wear and tear that results

from the physiological response to

stress” Allostatic Load

McEwen, B. S. (1998) Protective and Damaging Effects of Stress Mediators. New England J.Med. 338: 171-179

The process of stress pathogenesis (‘critical periods’)

Time

Health Emotional

Cognitive

Physical

Dispositional

Shifts

Behavioral

Affective

Physiological

Physiological

Dysregulation

HPA activity

Cardiovascular

Inflammation

Enduring

Emotional

States

Immediate

Stress

Response

Exposure

Event/

Hazard

Moments/ Minutes

Hours/ Days

Days/ Months

Months/ Years

Years/ Decades

Maladaptive (chronic stress)

Adaptive (acute stress)

Dysregulation/ Impairment

Mechanisms & Risk Regulators (critical period)

Distinguish immediate from enduring stress responses

What should we measure?

“Today/last few hours” …Argument (or avoided argument) …Overload at work or home …Traffic/weather

Everyday stress (daily hassles)

“Any idiot can handle a crisis—it’s this day-to-day living that wears you out.” —Anton Chekhov

“straw that broke the camel’s back”

“Trait” Reactivity

Reactivity is “a stable individual difference in response to stressors” (Cohen et al., 2000)

Daily Stress research has mostly focused on (stable) individual differences (high vs. low responders)

Few studies have examined time-varying (contextual) effects on daily stress

Daily Stress Response is operationalized by the slope relating level of stress on a given day to a person’s negative affect (NA) [or cortisol output]

6 daily

measurements

Burst 1 Burst 4 Burst 3 Burst 2 6 mos. 6 mos. 6 mos. 6 mos.

Burst 5

Measurement-Burst Design

6 daily

measurements 6 daily

measurements

6 daily

measurements

6 daily

measurements

Sample Cognitively intact, non-depressed, independent living adults (N=104) ages 65-95

Measures Daily negative affect (NA), daily stress (hassles), Background stress (30 days prior to each

burst)

(Nesselroade, 1991)

‘Reactivity’ varies more within than between persons

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Person Level Burst Level

% o

f to

tal

Var(

Reacti

vit

y)

Source Var(Reactivity) SE p-value

Between-Person 0.026 0.014 0.02

Within-Person 0.080 0.020 <.01

~24% of the variance in emotional responses is ‘stable’

Burst 1

severity

NA

Burst 2

severity

NA

Burst 3 Burst 4

severity

NA

severity

NA

severity

NA

severity

NA

P1

P2

Burst 5

severity

NA

severity

NA

severity

NA

severity

NA

Within-person variability in background stress (during 30 days prior to burst) predicted within-person variability in slopes

Low stress burst High stress burst

High stress burst Low stress burst

“Daily” Emotional Responses are a mixed bag

Most diary studies use 24 hour recall

Impossible to sequence stressor/event and emotions

The daily stress ‘response’ conflates immediate reactions and enduring mood states (prolonged effects)

Pathogenic Convey Risk (individual differences)

Experience Sampling Design

Query individuals about their mood, thoughts and experiences at pseudo-random times throughout the day

Completed surveys on palmtop computer… 1. Upon waking (WAKE)

2. At 5 random times throughout the day (BEEP) 3. Prior to going to bed (EOD)

…for 7 consecutive days

Lagged effects Enduring responses (3-6 hours)

Concurrent effects “Immediate” responses (0-3 hours)

Stressful Events Negative Affect

Fixed Effects

Time Variable Effect

Stressful events predict current and subsequent NA…

Current Event (t) (0-3 hours) b=4.57, p<.01

Prior Event (t-1) (3-6 hours) b=1.44, p<.01

Variances

Current Event (t) (0-3 hours)

Prior Event (t-1) (3-6 hours)

% Between-Person

13%

43%

Prolonged (lagged) responses exhibit relatively more stable (dispositional) variance

Differential Moderation of Current and Lagged Effects

Recent Social Exchanges Prior evening’s sleep Anticipated Stress

Contextual (state) Variables

Current Event Effects (Immediate)

Lagged Event Effects (enduring)

Personality (PA) Education Cognitive (fluid) function

Dispositional (‘stable’) Variables

What connects everyday stress to long-term health outcomes?

Time

Discrete

Events

Acute

Response

Health

Mental

Cognitive

Physical

Prolonged

Activation

(emotional/

physiological)

Chronic Exposure

Ongoing events and strains

Physiological

Dysregulation

HPA activity

Cardiovascular

Inflammation

An important mechanismChronic Stress

Perseverative Cognition (PC) “Repetitive thinking about problematic situations or events” (worry, rumination)

“I have thoughts I cannot stop”

“My thoughts frequently return to one idea”

“I tend to replay past events as I would have liked them to happen”

“When I have an important event coming up, I can’t stop thinking about it”

-- Endocrine response (Zoccola et al., 2008)

--Cardiac effects (Pieper et al., 2007)

-- Negative affect (NA) (Moberly et al., 2008)

--Cognition (Stawski et al., 2006)

Heuristic Model of Chronic Stress

Time

Discrete

Events

Acute

Response

Health

Mental

Cognitive

Physical

Prolonged

Activation

(emotional/

physiological)

Chronic Exposure

Ongoing events and strains

Physiological

Dysregulation

HPA activity

Cardiovascular

Inflammation

Months/years

Hours/days

Perseverative

Cognition

Perseverative Cognition & Severity Negative Affect

Within-Day

Prior Event (t-1)

Current Event (t)

(3-6 hours)

(0-3 hours)

Time Variable Effect

Severity

Thoughts

b= 0.21, p=.13

b=0.78, p<.01

Severity

Thoughts

b=0.03, ns

b=0.16, p=.01

How much you think about a stressor now predicts how you will feel later in the day

Severity & PC Negative Affect

Across-day

Prior Day Event (t-1) (24-48 hours)

Time Variable Effect

Severity

Thoughts

b=-0.36, ns

b=1.00, p<.01

How much you think about a stressor now also predicts how you feel at the end of the day tomorrow

Next steps…

1. Linking psychological/behavioral and biological mechanisms

2. Neural basis for PC

How do stressors ‘get under the skin’? (telomere, inflammation)

3. Why do people worry/ruminate?

What reinforces worry?

Engage/disengage attention Attentional bias

25

Colleagues

Robert Stawski

Jacquie Mogle

Liz Munoz

Stacey Scott

Dave Almeida

Bill Gerin

Nilam Ram

Joshua Smyth

Scott Hofer

Investigators/Fellows/Students

NIH AG-26728 ,12448, and AG26453

Daily Stress and Health Risk

Physical Health: Daily stress is associated with… greater risk of disease burden (10 year follow-up) greater risk of all-cause mortality (5-10 year follow-up) (Almeida and colleagues, in review)

Mental Health: Daily stress increases long-term risk depression (daily stress a stronger predictor than spousal/childhood abuse)

Cognitive Health: Responses to daily stress associated with lower executive function (Stawski et al. 2010) and working memory (Sliwinski et al., 2006)

Perseverative Cognition (PC) accounts for stress effects

Stress

Exposure

Metabolic Risk 27%*

Cortisol waking

rise

40%*

Sleep quality 45%**

Working memory 57%**

Percent of exposure effects on health outcomes accounted for by Perseverative Cognition tendencies

PC N=383 *p<.05; **p<.01