Transcript Document

Exercise and the Brain
Karen Lindgren, Ph.D.
Strength of mind is exercise, not rest
-Alexander Pope
It is exercise alone that supports the spirits, and
keeps the mind in vigor
- Marcus Tullius Cicero
Goals
• How does exercise benefit general health?
• How does exercise benefit neurological
health?
• What is the relationship between exercise,
mood, health, and cognition?
FORMAT
• GEOGRAPHY OF THE BRAIN
• WHAT IS NEUROPLASTICITY
• EXERCISE
– What it is
– Physiology
• EXERCISE AND THE BRAIN
– Simple connections
– Complex connections
The link should be clear
• Our brain is a physical organ
• Our brain is a thinking organ
The link should be clear
Exercise helps us physically
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strengthens: hearts, bones, lungs, blood vessels
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physical changes should be related to thinking
changes
Like our other organs, our brain is a constantly changing
organ
The brain: physical organ
• Geography of the brain
• Brain basics
– Neurons
– Blood vessels
– Neurotransmitters
Brain Geography
The brain: a thinking organ
• What is thinking?
– Cognition refers to any mental process
What is cognition?
Areas of cognition include:
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Arousal/alertness
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Attention/Concentration
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Sensory skills
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Motor skills
What is cognition?
Areas of cognition include:
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Language
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Visual Skills
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Memory
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Problem solving/judgment
moral reasoning
Neuroplasticity
• What is neuroplasticity?
– Refers to the ability of the brain to shape itself
according to experience
– Refers to physical change on a neuronal level
Neuroplasticity
• What changes when we learn?
– Neurons connect with other neurons
• Synapses strength changes with learning
• More synapses form between neurons
• Plasticity can also refer to physical change
based on our health
What is exercise?
• Types
– Cardiovascular
– Weight training (resistance training)
• Intensity
– Active lifestyle
– Light
– Vigorous
What happens when we exercise?
• Heart rate increases
• Endocrine system activates
– Pituitary gland releases human growth hormone
to increase production of bone, muscle, or
connective tissue cells.
Pituitary Gland
• Located in brain, limbic system
• “Master gland” -- influences:
– Thyroid: neck
– Adrenal: kidneys
What happens when we exercise?
Hormones respond
• Pituitary gland regulates thyroid gland
Thyroid: releases hormones
•
Increase heart rate and blood pressure
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Regulate body temperature
•
Elevate “alertness” in brain to increase concentration and
reaction time
What happens when we exercise?
Hormones respond
• Pituitary gland regulates adrenal gland
Adrenal: releases cortisol
• causes blood pressure to rise
• triggers increase in glucose
• acts as anti-inflammatory agent (repairs tissues)
• Curbs non-critical functions (e.g., thirst, urine, hunger)
• effects immune system
What happens when we exercise?
Hormones respond
• Pituitary gland regulates adrenal gland
Adrenal: releases aldosterone:
• bodily response to anticipate dehydration through impact on
kidney function.
What happens when we exercise?
Hormones respond
• Pituitary gland regulates adrenal gland
Adrenal: releases adrenaline:
• (fight or flight) mechanism
• stimulant, increases strength and frequency of heart
contractions.
• Speeds breakdown of stored carbs into glucose for muscle
energy and for the brain.
• Enlarges our pupils
Summary: Exercise
Vascular, pulmonary, and endocrine systems are activated
• Carbs breakdown into glucose in blood to provide
energy for muscles
• Blood flow increases through heart rate, blood
pressure to get nutrients to muscles
• Improved concentration and reaction time
• Decreased thirst, less output
SECTION BREAK
• GEOGRAPHY OF THE BRAIN
• WHAT IS NEUROPLASTICITY
• EXERCISE
– What it is
– Physiology
• EXERCISE AND THE BRAIN
– Simple connections
– Complex connections
Exercise and the Brain:
How do we know they are linked
• Studies vary greatly (meta-analysis, Kramer et al)
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Age, gender
Length of exercise (session length, session number)
Exercise type varies
Method of reporting varies (often self-report)
Method of reporting cognitive skill varies (e.g., MMSE
screen, neuropsych, presence of dementia)
What is the link?
• Simple links
– Simple exercise – walking– has beneficial effects
– Simple mind/body benefits: mindfulness training, yoga
• Complex links
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Prevents primary neurologic disease
Promotes healthy normal aging
Neuroplasticity
Improved mood--- improved thinking
Simple connections
• Exercise improves blood flow to the brain
• Is increased blood flow related to improved
cognition?
Simple Connections
• Physical effects of exercise
– Increased blood flow to the brain
• Blood volume increases
• Blood flow is more “predictable”
• Small vessels grow – increase in number
– Study of 16 women aged 60 and older, walking briskly
3-4 times per week, improved blood flow up to 15 %
Simple Connections
• Physical effects of exercise
– Brings O2, glucose, nutrients to brain cells, vital for
cell health
– Cell growth: supports new connections, particularly in
hippocampus- memory
– Blood washes away “metabolic wastes” such as
“amyloid beta protein” (implicated in development of
Alzheimers)
Simple connections
Walking:
• Increases blood circulation
• Increased oxygen and glucose to the brain
• Not strenuous- muscles do not use extra oxygen
and glucose as in more strenuous exercise
In sum, you oxygenate your brain
“Clear your head”
What is the link?
• Simple links
– Simple exercise – walking– has beneficial effects
– Simple mind/body benefits: mindfulness training, yoga
• Complex links
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Prevents primary neurologic disease
Promotes healthy normal aging
Neuroplasticity
Improved mood--- improved thinking
Exercise prevents vascular disease
• Vascular disease
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Cholesterol lowering effects of exercise
Exercise lowers blood pressure:
Increased blood flow
Increased vessels
• The health benefits decrease risk for stroke
Exercise promotes healthy aging
• Normal Aging
– Ameliorates decline: Canadian researchers1 examined
active lifestyle for “elderly” individuals over 2-5 years,
showed stability in cognitive functioning for
individuals who were active, greater change if
sedentary.
– 90% of individuals with greatest daily energy scored
consistently on tests each year
– Activities included walking, cooking, cleaning
– 1Archives of Internal Medicine, 2011
Exercise promotes healthy aging
• Normal Aging
– More specifically, women in 70’s with vascular
disease showed a slower rate of cognitive decline
than the active group..
Exercise promotes healthy aging
• Normal Aging
– A second study2 showed that light duty weight
training has neurological effects.
– After one year, older women who lifted 2x per week
showed changes on both functional MRIs and
cognitive tests.
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2Neurobiology
of Aging, 2011
Exercise promotes healthy aging
• Normal Aging: start early!
– Mayo clinic study of 1,126 individuals with
“normal cognition” (as opposed to Mild cognitive
impairment)3
– Individuals with Moderate exercise during midlife
were less likely to develop impairment in later life
– 3Archives of Neurology, 2011
Exercise promotes healthy aging
– Exercise prevents onset of dementia
– Meta analysis of 1600 research papers examining
role of exercise in perserving cognitive abilities
– Conclusion: Important therapy against dementia
Exercise promotes healthy aging
– “…you can make a very compelling argument for
exercise as a disease-modifying strategy to
prevent dementia and mild cognitive impairment,
and for favorably modifying these processes once
they have developed.”
– J. Eric Ahlskog, M.D., Ph.D., neurologist, Mayo Clinic
Exercise promotes healthy aging
• Other Neurologic Disease
– Mild cognitive impairment (MCI): each year, 10-15% of
individuals with mild cognitive impairment will develop
dementia5.
– Study: 33 adults with MCI. 23 assigned randomly to aerobic
group and exercised at high intensity levels for 45-60 minutes
per day, 4 days per week, with a trainer. Control group: 10
individuals performed supervised stretching with low heart rate.
– 5Archives of Neurology, 2011
Exercise promotes healthy aging
• Mild Cognitive Impairment
– Found improved fitness (body fat analysis,
metabolic markers) and improved cognition.
– Cognitive improvements were more marked in
women than men. This may be related to body’s
use of insulin, glucose, and cortisol, which differed
between the sexes.
Exercise promotes healthy aging
• Other Neurologic Disease
– Parkinson’s Disease
• Researchers4 followed 140,000 people with avg. age of 63
for 10 years.
• Moderate to vigorous activity levels were related to a 40%
less chance to develop Parkinsons than those with light or
no activity levels.
• Not clear if the relationship is focused on short term or long
term (i.e., do you need to start exercising at 40?)
4American
Academy of Neurology, 2007
What is the link?
• Simple links
– Simple exercise – walking– has beneficial effects
– Simple mind/body benefits: mindfulness training, yoga
• Complex links
–
–
–
–
Prevents primary neurologic disease
Promotes healthy normal aging
Neuroplasticity
Improved mood--- improved thinking
Exercise and Stress
• Chronic cortisol release leads to detrimental
effects:
– Chronically high cortisol reduces dopamine
• Exercise initially mimics this effect
• Regular exercise training helps to reduce cortisol
levels (e.g., a 20 minute walk ceases to be
“stressful” to the body).
Mood Benefits
• Exercise improves stress tolerance:
– Exercise causes a drop in stress hormones
– Improves “resilience” to stress
– Brain-derived neurotrophic factors (BDNF)
• “fertilizer” of the brain’s neurons
• Grow more quickly, develop stronger connections
• Associated with improved cognition, mood
Mood Benefits
• Exercise improves stress tolerance:
– Rats assigned to 4 groups6:
• Engaged in “voluntary running”
• Given antidepressants
• Both
• Neither
– Rats then underwent a 2-day “forced swimming” procedure
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6 California State University, 2001
Mood Benefits
• Exercise improves stress tolerance:
– Results:
• BDNF levels in untreated animals were depressed
• Animals that were given physical training or
antidepressants had BDNF restored to baseline
• Animals with both showed increase in hippocampal
BDNF well above baseline.
Mood Benefits
• Improved mood improves cognition:
– Exercise has an “antidepressant effect”
– Antidepressant effect of running was associate with
more cell growth in hippocampus9
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9 Proceedings of the Academy of Natural Sciences, 2010
What is the link?
• Simple links
– Simple exercise – walking– has beneficial effects
– Simple mind/body benefits: mindfulness training, yoga
• Complex links
–
–
–
–
Prevents primary neurologic disease
Promotes healthy normal aging
Neuroplasticity
Improved mood--- improved thinking
Does exercise foster neuroplasticity?
• Exercise increased growth factors in brain making it easier to
grow new connections10
• Mice that ran on a wheel had twice as many new brain cells as
mice housed in standard cages11. As a comparison, provided
mice with other “enriched” environments (e.g., “free swim”)only running produced the effect.
– Growth was in the hippocampus (learning and memory)
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10UCLA,
11
2011
Nature Neuroscience, 1999
Does exercise foster neuroplasticity?
Meta-analysis of 18 controlled studies of
cognitive function and aerobic fitness for
individuals aged 55-8013
13 Psychological
Sciences, 2003
Does exercise foster neuroplasticity?
Results:
– Exercise had clear, selective cognitive benefits for
attention, organization, planning
– Frontal skills
– Strength training combined with aerobic fitness
was most effective
– Exercise sessions of less than 30 minutes per
session had little impact
Does exercise foster neuroplasticity?
– Brain-derived neurotrophic factors (BDNF)
– “fertilizer” of the brain’s neurons
• Grow more quickly, develop stronger connections
– Associated with improved cognition, mood
Does exercise foster neuroplasticity?
– Brain-derived neurotrophic factors (BDNF)
– produced in the brain during endurance training
– produced peripherally in resistance training, circulates
to the brain
–
University of Florida study: 20 college aged men14
• Increased neurotrophic factors at 1, 30 and 60 minutes after
endurance training
•
14
American College of Sports Medicine, 2010
What is the link?
• Simple links
– Simple exercise – walking– has beneficial effects
– Simple mind/body benefits: mindfulness training, yoga
• Complex links
–
–
–
–
Prevents primary neurologic disease
Promotes healthy normal aging
Neuroplasticity
Improved mood--- improved thinking
Cognitive exercise
• Cognitive exercise has similar effects
• Two together have strongest effects
• Visualizing exercise improves neuroplasticity as
well
• Best exercise is novel tasks: at any level
Yoga is cognitive and physical
• Yoga, mind/body connection is good for us
• Yoga decreases depression, anxiety,
hypertension, stress
Yoga is cognitive and physical
• Yoga: the research
– Enhanced effects of meditation alone
– Study of novice participants in a 12-week yoga
training program15
– 15 Journal of Alternative and Complementary Medicine, 2009
Yoga is cognitive and physical
• Results:
– EEG changes were greater in left hemisphere
– Participants experienced greater ability to activate their
brain, particularly right hemisphere, through yoga
– Increased blood flow in right pre-frontal cortex
– Changes in amygdala, sensorimotor cortex consistent with
changes in processing emotions and sensory phenomena
One last point….
• Exercise improves our sleep
Conclusions
• Cognition is complex
• THINKING-MOOD-BRAIN all connected to
health
Conclusions
• Exercise is shown to positively affect cognition
in the following ways:
– Improving blood circulation
– Increased availability of oxygen and nutrients
– Clears metabolic waste
Conclusions
• Exercise prevents disease:
– Cardiovascular effects decrease risk of stroke
– Shown to prevent Alzheimers, Parkinsons, mild
cognitive impairment onset
Conclusions
• Regular exercise decreases our symptoms of
stress (e.g., lowers cortisol)
• Improves resiliency
• Improves mood- acts as an antidepressant
• Increases growth of neurons in key areas:
– Frontal lobes, hippocampus
Practical Advice
–The Basics:
– Do something
– Stick with what you stick with
– Every bit counts: even 20 minutes of exercise
facilitates brain function
Practical Advice
– The Details:
- Exercise has short term effects of mood,
concentration, memory and stress that last
for several hours after exercise
– -Moderate exercise for a six month time
frame is beneficial to begin to see long term
benefits
Practical Advice
– The Details:
- Exercise should continue with age
- Exercise that encourages cognitive focus has
additional benefits : find something that
challenges you (ballroom dancing, a new class,
yoga, etc.)
- Exercise that is interesting is also good (vary
your walk!)
Special Information: Brain Injury
• Exercise after concussion is not
recommended:
– REST IS RECOMMENDED
Special Information: Brain Injury
• For all these reasons, exercise is important for
long term recovery from a brain injury
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Promotes mood
Promotes stable sleep patterns
Promotes physical health
Promotes self-efficacy, improved views of health
Promotes neurogenesis in animal models
Increased blood flow in hippocampus
Thank you!!
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