Transcript Chapter 7 - Delmar

Chapter 7
Resistance-Training Strategies for
Individuals with Chronic Heart Failure
Copyright © 2010 Delmar, Cengage Learning. ALL RIGHTS RESERVED.
Heart Failure Defined
• Pathological state in which abnormality of
cardiac function causes failure of heart to
pump blood at rate commensurate with
requirements of metabolizing tissues
– Or to do so only from elevated filling pressure
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Chronic Heart Failure Defined
• Multi-system syndrome with multiple
pathological abnormalities that reduce
exercise tolerance and contribute to
functional disability
• Systolic dysfunction
– Reduced pumping capacity
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Exercise Intolerance and
Resistance Training
• Exercise tolerance
– Inability to sustain sub-maximal level of
exercise/activity
• Previously contraindication for resistance
training
• Now included in conjunction with aerobic
exercise
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Prevalence of Chronic Heart Failure
• Affects approximately 5 million individuals
in US
• More than 550,000 individuals diagnosed
each year
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Prevalence of Chronic Heart Failure
• At age 65, rate increases from 2 to 3 percent
– Affecting one in 100 individuals
• Over age 80, affects more than 80 percent
of individuals
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Economic Impact
• Most common cause of hospitalization for
people age 65 or more
• Individuals unable to perform activities of
daily living due to deconditioning, dyspnea,
and fatigue
• Approximately $30 billion total direct cost
annually
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Common Symptoms
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Muscle weakness
Dyspnea on exertion
General fatigue
Cardiovascular (central) and muscular
(peripheral) dysfunction contribute to
symptoms of heart failure
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Etiologic Factors
• Ischemic heart disease
– Underlying factor in approximately 60 percent of cases
• Hypertensive heart disease
• Valvular heart disease
• Variety of metabolic, infectious, and toxic
agents
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“Muscle Hypothesis”
• Connection between cardiovascular and
skeletal muscle dysfunction contributes to
symptoms of heart failure
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Effects of Chronic Heart Failure
on Skeletal Muscle
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Reduces blood flow
Increases blood lactate levels during exercise
Increases fatigue rates
Causes structural alterations in peripheral
vasculature
• Causes muscle atrophy and loss of muscle
strength/endurance
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Effects of Chronic Heart Failure at
Muscular Level
• Reduces slow-twitch oxidative fibers
– Type I
• Increases fast glycolytic fibers
– Type IIB
• Reduces mitochondrial function
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Effects of Chronic Heart Failure at
Muscular Level
• Increases inducible nitric oxide synthase
(iNOS) and nitric oxide associated with
down-regulation of mitochondrial creatine
kinase expression
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Benefits of Resistance Training
• Increases skeletal muscle and endothelial
function
– Decreasing negative effects associated with “muscle
hypothesis”
• Improves physical and psychosocial factors
• Decreases fatigue
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Benefits of Resistance Training
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Improves emotional function
Increases functional ability
Improves peripheral blood flow
Decreases sympathetic activation
Improves heart rate variability
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Benefits of Resistance Training
• May improve autonomic function
• Increases muscle mitochondria size
• Improves muscle strength and endurance
– Allowing greater efficiency when performing activities
of daily living
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Research Supports Resistance
Training
• Cumulative research results indicate
resistance training leads to increases in:
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Muscular strength
Muscular endurance
Quality of life
Functional measures
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Research Limitations
• Choice of subjects has mainly been
“younger” males at low to moderate risk
– Age 40 to 60
• Many studies not reproducible due to
various factors
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Research Limitations
• Typical 12-week program may be
insufficient to impact both neural and
muscle adaptations
• Focus on localized training strategies not
ideal for long-term compliance
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Program Design Considerations
• Individuals in highest risk level due to
greater overall morbidity/mortality rates
• Extensive medical and physical activity
history required prior to training
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Program Design Considerations
• Other co-morbidities
– E.g., diabetes, age
• Degree of severity of heart failure
– Use categorization system established by American
Heart Association (AHA) and American College of
Cardiology (ACC)
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Heart Failure Classification System
• Stage A
– At risk for developing heart failure
• Stage B
– Asymptomatic and free of structural abnormalities
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Heart Failure Classification System
• Stage C
– Structural abnormalities with/without mild to moderate
symptoms
• Stage D
– Advanced structural concerns
– Quite limiting symptoms
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New York Heart Association
(NYHA) Classification System
• Class I
– Level of exertion that would elicit symptoms for
normal person
• Class II
– Symptoms with ordinary exertion
• Class III
– Symptoms during less than ordinary exertion
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New York Heart Association
(NYHA) Classification System
• Class IV
– Symptoms at rest
• Individuals with symptoms in Class II-IV
also fall within AHA/ACC Stage C and D
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Drug Regimen Considerations
• Consider possible drug side effects when
planning training
• Diuretics reduce blood volume and edema
• Vasodilators reduce blood pressure and
systemic vascular resistance
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Drug Regimen Considerations
• Beta-adrenergic receptor blockers interrupt
“toxic effects” of over-active sympathetic
nervous system
• Digoxin may be used
– Also controversial
• Antiplatelet and anticoagulation therapies
• Aldosterone antagonist
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Exercise Testing Requirements
• Physical examination
• Symptom-limited cardiopulmonary exercise
test using modified Naughton protocol
• Resting echocardiogram
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Testing Protocol
• Stress applied during test should reflect
combination of static and dynamic loads on
heart occurring during resistance training
• Echocardiographic stress test using leg
press simulates training session
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Testing Protocol
• Measure:
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Heart rate
Blood pressure
End diastolic volume
End systolic volume
Stroke volume
Ejection fraction
Cardiac output
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Testing Protocol
• If all variables assessed within normal
limits, resistance training likely to be safe
• Next step:
– Maximal strength testing
• Measure muscle strength by 1 RM method
for all exercises to be included in resistance
training program
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Contraindications for Resistance
Training
• Post-exercise hypotension
• Arrhythmias
• Worsening heart failure symptoms:
– Weight gain of 1.5 to 2.0 kilograms (kg) over previous
three to five days
– Increased heart rate and dyspnea
– Auscultatory findings of pulmonary edema
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Cautions
• Some individuals experience temporary
increase in fluid accumulation two to six
weeks after starting exercise
• Take care during lifting exercises due to
possibly altered reflex response to
positional changes
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Program Components
• Consider individual’s loss of muscular
endurance
– Contributes to up to 40 percent of exercise intolerance
• First 12 weeks:
– Circuit training protocol
– Eight weeks of machines followed by four weeks
adding free weights
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Program Components
• First 12 weeks:
– Use sequence with minimal rest between exercises
• 30 to 60 seconds
– Perform approximately 8 to 12 repetitions of each
exercise per circuit
• 50 to 80 percent of 1 RM
– Progress to 3 sets of 8 repetitions at 80 percent of 1 RM
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Program Components
• Second 12-weeks:
– Two, six-week cycles
• Cycle 1 at club
• Cycle 2 at both home and club
• Review sample 24-Week Program
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Additional Training
Considerations
• Should be entire body progressive
resistance training program
• Ensure adequate rest/recovery
– Critical to optimal outcomes
• Understand how varied differences in
training intensity prevent training plateaus
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Additional Training
Considerations
• Constantly supervise and spot
• Properly orientate individuals to each
procedure and piece of equipment
• Perform intermittent monitoring of heart
rate and blood pressure
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