prevent injuries and cognitive decline€¦ · prevent injuries and cognitive decline david...

$: Prevent Injuries and Cognitive Decline€¦ · Prevent Injuries and Cognitive Decline David Raichlen School of Anthropology University of Arizona. 95% Of hip fractures come from falls$
Balance Exercises and Fitness to Prevent Injuries and Cognitive Decline

David Raichlen

School of Anthropology

University of Arizona

95%Of hip

fractures come from

falls

Falls are most common cause of TBI

We spend ~$30 Billion/year on fall-related injuries

Outcomes

CDC

CDC

Increased Fall Risk Is NOT Inevitable

Nothing in Biology Makes Sense Except in the Light of Evolution

-Theodosius Dobzhansky

Road map:1) Evolutionary history of aging and exercise2) Exercise and fall risk: predictors and prevention3) What can you do to reduce fall risk?

We evolved to get old, but not frail

0102030405060708090

Life

span

Grandparents care for offspring when parents foraging

This lifestyle requires long, physically active days away from camp

Why long life?Grandmother Hypothesis

Must be healthy and active in old age (Falls should be rare!)

Physically active lifestyle was the key to successful aging in our ancestors

Exercise: key to living longer?

Wen et al., 2011

8 year study of over 400,000 Taiwanese men and women

walking

jogging

Staying Healthy Longer Too

Fries, 1996

0

0.05

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0.15

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0.25

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0.35

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0.45

0.5

55-59 60-64 65-69 70-74 75-79 80-84

Dis

abili

ty S

core

Runners

NonRunners

Age

Why long life?

Grandmother Hypothesis

Physically active lifestyle the key to successful aging (falls are rare)

We live in a mismatch environment: Our bodies evolved to be active

What Causes Falls?Most falls occur during walking

Berg et al 1997; Robinovitch et al. 2013

Fall Predictors

1) Muscle weakness (Moreland et al., 2004)

Traditional View:

Instability, poor balance, and lack strength to recover from a trip

Muscle Strength and Fall Risk

Moreland et al. 2004

Meta-analysis (study of studies):Compiled data from 13 studies

Total n = 6146 older adults

Odds of falling in future if subject displays muscle weakness



Odds Ratio (OR): Odds that an outcome (fall) will occur given a particular condition (muscle weakness)

1 = no difference

0

0.5

1

1.5

2

2.5

Lower limb Upper Limb

Od

ds

Rat

io

Fall Predictors

1) Muscle weakness

2) Cognitive decline

Traditional View: Novel View:

May be responsible for trips and stumbles

Cognition and Walking

Executive function: Management of cognitive

processes

1) Planning and execution2) Response inhibition3) Task flexibility/multi-task

Walking is a complex task that requires coordination between brain and body

Frontal Lobe



processes



Making decisions in a complex environment



processes



Filter out distractions; Focus attention on gait



processes



Walk and talk at the same time

Decline in EF affects walking

became stronger under dual tasks conditions among el-

derly nondemented fallers and among patients with Par-

kinson’s disease, whereas such associations were not

observed in healthy young adults. Similarly, Hausdorff et

al. showed that better gait performance (e.g., higher gait

speed, lower stride time variability) was associated with

better scores on a “catch game,” a complex motor task,

but this association did not exist for finger tapping, a

relatively simple motor task.30 Associations between EF

and performance of balance and mobility were also ob-

served in stroke patients, even after adjustment for age,

quadriceps strength of the paretic side and current phys-

ical activity level.31

The earlier mentioned studies demonstrate how gait is

related to EF. It appears that this association is stronger

if the locomotor task is more challenging (e.g., obstacle

course) and/or if the normal gait pattern is already altered

(e.g., in patient populations). The results of the InChianti

and other studies suggest that the reliance on EF in-

creases as the locomotor task becomes more difficult and

challenging. Still, many questions remain about these

relationships. For example, while there is some evidence

suggesting that a decline in EF ability may actually

contribute to alterations in walking abilities, cause and

effect has not been definitively demonstrated. In addi-

tion, most studies correlated only selected parameters of

gait (e.g., speed or gait variability) with selected features

of EF. Although associations were observed, the inclu-

sion of a wider array of measures may provide a broader

picture of the interdependence between gait and EF and

may help to define if and how specific EF properties

affect specific aspects of walking.

ATTENTION

Definition of Attention

Attention may be considered a specific example of

EF.7,32 The term covers a “number of different processes

that are related aspects of how the organism becomes

receptive to stimuli and how it may begin processing

incoming or attended-to excitation, whether internal or

external.”5 There is, however, “no single and clear-cut

definition of attention.”5 Posner et al. view attention as

an anatomical network whose “primary purpose is to

influence the operation of other brain networks.”33 At-

tention can be classified into separate functions, includ-

ing focused or selective, sustained, divided and alternat-

ing, although these distinctions are somewhat artificial.

Selective attention, which enables filtering of stimulus

information34 and suppression of distractors, is com-

monly referred to as “concentration.”5 Sustained atten-

tion refers to the ability to maintain attention to a task

over a period of time.5,34 Divided attention refers to the

ability to carry out more than one task at the same time

and alternating attention refers to rapid shifting of atten-

tion from one task to another.5,34 Here we focus primarily

on divided attention. This type of attention plays an

important role in walking in multitasking and changing

situations, serves as a common tool for examining the

attentional demands of various tasks, including walking,

and has clinical implications for fall risk.

Models of Dual Tasking

During the past 2 decades, many studies have inves-

tigated whether gait requires attention. Dual tasking is

the most popular method for testing this question. This

involves challenging attentional capacities, specifically

the ability to divide attention. A priori, if gait is auto-

matic and does not require attention, then simultaneous

execution of an additional task should not affect gait or

the performance of the other task. Before we review the

studies that provide evidence that gait is indeed an at-

tention-demanding, high-level, controlled task, we first

briefly summarize the neuropsychology theories that

have been proposed to explain why there are dual tasking

costs in other situations.

Difficulties in the simultaneous performance of two or

more tasks have led to the development of several neu-

ropsychological theories on human information process-

ing. Explanations generally revolve around the capacity-

sharing theory, the bottleneck theory or the multiple

resource models theory. The capacity-sharing theory

FIG. 1. Association between gait speed and performance on the TMTin the InCHIANTI study. Subjects with poor and intermediate perfor-mance in the TMT (i.e., large increase when going from TMT-A toTMT-B) had decreased gait speed, especially on the obstacle course.From Ble et al.27

332 G. YOGEV-SELIGMANN ET AL.

Movement Disorders, Vol. 23, No. 3, 2008

Yogev-Seligman et al., 2008

Performance on Executive Function TestGood Medium Poor Good Medium Poor

Wal

kin

g sp

eed

(m

/se

c)4-meter course

Usual pace

7-meter course with obstaclesFastpace

Executive Function Predicts Fall Risk

Herman et al. 2010

0

10

20

30

40

50

60

0 5 10 15 20 25

% o

f su

bje

cts

wh

o f

ell

Time to first fall (months)

High Executive Function

Low Executive Function

Dual-task paradigm

0

1

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3

4

5

6

7

8

9

10

Dual-task Lower limb Upper Limb

Od

ds

Rat

ioOdds of Falling

Beauchot et al., 2008

Odds of falling when gait changes during multi-tasking

1 = no difference

n = 2290 muscle weakness muscle weakness

Fall Risk Model

Reduced Executive Function

Easily Distracted Can’t multi-task

Muscle Weakness(can’t recover)

Increased trips& stumbles Fall

Prevention

Exercise can increase muscle strength

Exercise can improve executive function

Fall Prevention

1) Muscle weakness

Traditional View:

Exercise Improves Muscle Mass

0

5

10

15

20

25

30

35

Baseline 2 months

On

e R

ep

Max

imu

m L

eft

(k

g)

Strength Training Improves Muscle Function

Fiatarone et al. 1990

3 x per week; ~5 minutes of lifts

0

5

10

15

20

25

30

35

Baseline 2 months

On

e R

ep

Max

imu

m L

eft

(k

g)



0

5

10

15

20

25

30

35

Baseline 2 months

On

e R

ep

Max

imu

m L

eft

(k

g)

3 x per week; ~5 minutes of lifts

Fall Prevention

1) Muscle weakness

2) Cognitive decline (e.g., multi-tasking)


✔

Can exercise reduce cognitive decline?

Aerobic Exercise Improves Cognition

Hillman et al., 2008

Analysis of 18 studies show exercise training benefits for cognition in older adults for multiple cognitive domains, but especially for executive abilities

Size

of

the

Effe

ct

Executive Controlled Spatial Speed

ControlExercise

Aerobic exercise increases brain volume

Healthy elderly adults randomly assigned to aerobic exercise for 6-months, 3 hrs/week had increased brain volume in gray matter (GM; blue) and white matter (WM; yellow) compared to a non-exercise group.

Colcombe et al., 2006

Frontal WM

Frontal GM

59 Participants

Exercise Improves Fall Risk Independent of Muscle Strength

0

20

40

60

80

100

120

Control Exercise

Falls

pe

r 1

00

pe

rso

ns

0

5

10

15

20

25

30

Control Exercise

Kn

ee

ext

en

sor

stre

ngt

h

Exercise program reduces fall risk without increasing muscle strength (meta-analysis of a standard fall prevention program) Robertson et al., 2002

Falls per 100 persons Muscle Strength

Meta-analysis of Exercise Studies

~55% reduction in falls in individuals in exercise programs (aerobic + strength training) Petridou et al., 2009

597 subjects in five RCTs

55%

Fall Prevention

1) Muscle weakness

2) Cognitive declines (e.g., multi-tasking)


✔

✔

Fall Risk Model


Easily Distracted Can’t multi-task


Increased trips& stumbles Fall

Fall Risk Model



Fall

What Can You Do?

Focus on two main activities:

– Aerobic

– Strength/balance

Aerobic Exercise

Activities that increase your heart rate: brisk walking, cycling, swimming

Suggestions for daily life changes

AgeMax. HR

(220-Age)Target HRs(60-70%)

65 155 93-109

70 150 90-105

75 145 87-102

80 140 84-98

85 135 81-95

90 130 78-91

Work your way up to moderate intensity

American Heart Association Guidelines

Suggestions for daily life changesWork your way up to moderate intensity

Light intensity:Can talk and sing without problemNo change in breathing patterns Moderate intensity:

Change in breathing, but not out of breathCan talk, but not sing

Strength Training

National Institute on Aging at NIH:http://go4life.nia.nih.gov

National Institute on Aging at NIH:http://go4life.nia.nih.gov

Find Activities and Exercises Here


How to start? Small changes can add up to big results

Increasing stair use can improve aerobic fitness by 10%

Park farther away: Lifestyle change comparable to structured

program in intervention study

Ross and McGuire et al., 2011; Meyer et al., 2010; Dunn et al., 1999


Make it a priority: Schedule exercise into your calendar like an appointment

Making exercise social improves adherence: 84% vs. 60% after 6 monthsCox et al., 2003


Keep it fun: You will keep doing activities if you enjoy them

Ryan et al., 1997Wankel, 1993

Start Today

Remember: Activity is in our Genes

Grandmother Hypothesis

Physically active lifestyle allows for successful aging

Thanks!

Thank You Supporters!

Causes of Falls

1. Accident/environment based (~31%)

2. Gait disorders (~17%)

3. Symptoms of underlying diseases account for rest

Rubenstein 2006 Age and Ageing

Ambrose et al. 2012

Strength

Three Suggestions

• Start small

• Make a plan (exercise is a priority)

• Keep it fun (you do what you enjoy)


Make a plan: Ask a friend to take a walk or join a group exercise class/activity

Making exercise social improves adherence: 84% vs. 60% after 6 months

Cox et al., Prev Med, 2003

Suggestions for daily life changesWork your way up to moderate intensity

Light intensity:Can talk and sing without problemNo change in breathing patterns Moderate intensity:

Change in breathing, but not out of breathCan talk, but not sing

Dual-Task Performance and Fall Risk



1 =

No

dif

fere

nce

in o

dd

s o

f fa

llin

g



Odds Ratio (OR): Odds that an outcome (fall) will occur given a particular condition (muscle weakness)

1 = no difference

Higher risk

Executive Function Predicts Fall Risk

Herman et al. 2010 J. Gerontology

Meta-analysis of Exercise RCTs

~55% reduction in falls in individuals in exercise programs (aerobic + strength training) Petridou et al., 2009

Humans Have Long Lifespans

Finch C E PNAS 2010;107:1718-1724

Odds of Falling

0123456789

10

Retrospective Prospective

Od

ds

Rat

io



1 = no difference

Hig

her

od

ds

0

1

2

3

4

5

6

Mill

ion

s o

f ye

ars

ago

From ~7-2 Ma: Bipedal fruit eating apes(Australopithecus)

2 Ma: Hunting and gathering (Homo)

Human Evolution

Fall Risk Model

Reduced Cognitive Function

Distraction

Slow decision making


Increased trips& stumbles

Fall

Exercise Training and Dual-Task Performance

-5

0

5

10

15

20

25

30

35

Simultaneous training Cognitive training Control group

Pe

rce

nt

Re

du

ctio

n in

Gai

t V

aria

bili

ty

Theill et al., 2013

Exercise is Good For Us

We live in a mismatch environment: Our bodies evolved to be active

Exercise is the “magic pill”

Question

Is exercise the key to reducing fall risk?

Hip fractures in 75 and older (per 100k) Nigeria: 8.0Britain: 190.8

Adebajo et al. 1991

Fall risk in more active populations?

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