Copyright 2005 Lippincott Williams & Wilkins Chapter 6 Impaired Aerobic Capacity/Endurance
Feb 22, 2016
Copyright 2005 Lippincott Williams & Wilkins
Chapter 6Impaired Aerobic
Capacity/Endurance
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Physiology of Aerobic Capacity and Endurance
Physical Activity Exercise Physical Fitness
Cardiorespiratory Endurance
The ability of the whole body to sustain prolonged exercise.
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Energy Sources Used During Aerobic Exercise
Fat, Carbohydrates, Protein
ATP ATP ATP
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Metabolic Pathways
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Fuel Source Selection During Exercise
CHO is the preferred fuel source for ATP to supply
the body with energy during exercise.
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Normal and Abnormal Response to Acute Aerobic Exercise
Heart Rate – Linear relationship between HR and intensity of exercise (factors – age, fitness level, type of activity, disease, medications, bl volume, environment).
Stroke Volume – Workload and SV increase linearly until 50% aerobic capacity (factors – body composition and exercise intensity).
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Cardiac Output
• Cardiac output and workload increase linearly b/c of increases in HR and SV (factors – age, posture, body size, disease, physical conditioning).
• Arterial/venous oxygen difference – As exercise increases a-VO2 diff increases linearly.
• Blood flow – at rest 15–20% muscle.During exercise 80–85% muscle.
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• Blood pressure – Systolic BP linearly with work load. Diastolic BP changes very little.
• Pulmonary ventilation – During exercise, breathing increases to facilitate amount of air exchanged per minute. Tidal volume and respiratory rate increase in proportion to exercise.
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Physiologic and Psychological Adaptations to Cardiorespiratory Endurance Training
Increased• Heart wt, vol• Left ventricle size• SV, cardiac output• Hemoglobin• Peripheral capillary
formation• Respiratory rate• PV during max exercise• Vo2, Vo2 different during
maximal exercise
Decreased• Resting and submax HRs• Time required to return to
resting levels• Systolic/diastolic pressure• Resting and submaximal
respiratory rates• Body fat
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Psychologic Benefits of Training
ImprovedMoodsDepressionAnxietyPsychological well-beingPerceived quality of life
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Causes of Impaired Aerobic Capacity/Rehabilitation Indications
Heart MuscleCoronary artery
diseasePericarditisCongestive heart
failureAneurysms
Heart ValvesRheumatic feverEndocarditisMitral valve prolapseCongenital deformities
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Nervous SystemArrythmiase.g., tachycardia,
bradycardia
Peripheral Vascular Disease
Arterial disorders, venous disorders, lymphatic disorders
e.g., atherosclerosis, embolism, Buerger’s disease, Raynaud’s, deep vein thrombosis, lymphedema, venous stasis
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Examination/Evaluation of Aerobic Capacity
Examination and evaluation of CV and respiratory systems should be included in exam of all clients
Tests IdentifyPresence of diseaseEstablishing a
baseline aerobic capacity
Measuring change in aerobic capacity
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Patient/Client History
General demographic informationSocial/health habitsGeneral health status (physical, role, social
functioning, etc.)Clinical tests (blood cholesterol)Medications
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Systems Review
Examination of other major body systems
Skin integrityMuscle strengthJoint ROMBalanceGait functionAbility to make needs
known
CommunicationAffectCognitionLanguageLearning style
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Screening Examination
Pain in chest, neck, jaws, or areas of ischemia
Shortness of breath at rest or with mild exertion
Dizziness or syncopeOrthopneaAnkle edema
Palpitations or tachycardia
Intermittent claudication
Known heart murmurUnusual fatigue or
shortness of breath with usual activities
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Tests and Measures
Maximal Graded Exercise Tests Graded or variable workload over 8-12 min.
Commonly done in conjunction with ECG.
Submaximal Graded Exercise Tests Estimates VO2max. Includes bicycle ergometer
tests (Astrand-Ryhming, YMCA protocol), treadmill tests, step tests, field tests.
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Anthropometric Characteristics
Hydrostatic – gold standard (requires expensive specialized equipment and patient tolerance)
BMI (body mass index)Bioelectric impedanceNear-infrared interactanceSkinfold measurements
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Circulation
Blood pressureHeart rate, rhythm,
and patternRespiratory rate,
rhythm, and pattern
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Therapeutic Exercise Intervention
Objective of exercise prescription is to assist in the adoption of regular physical activity as a lifestyle habit.
Consider – behavioral characteristics, personal goals, exercise preferences of the individual.
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Mode of Intervention
WalkingJoggingCross-country skiingBicycling
Rope jumpingRowingSwimming (or water
aerobics)Aerobic dance
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Dosage – Training Type
Continuous – (e.g., 30 minutes using 1 or 2 exercises)
Interval Training – Multiple bouts of higher intensity w/ short periods of rest/light activity (e.g., 2 minutes)
Circuit Training - Individual rotates through series of exercise stations.
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Dosage – Training Sequence
1. Initial warm up (5–10 minutes) of large muscle groups (walking, cycling, etc.)
2. Stretching exercises3. More vigorous
cardiovascular exercises as prescribed
4. Cool down with stretching
1&4
2&4
3
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Dosage – Frequency
Determined considering patient’s goalsOptimal frequency – 3–5 times per week
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Dosage – Intensity
Based on overload principle and within the patient’s functional limitations
Select a training range to allow for flexibility (e.g., 60–70% of HR max)
60–80% has been the general recommendation
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Dosage – Duration
Depends on goals, frequency, intensity & conditioning level of patient
Optimal duration is 20–30 minutes per session
If unable, several 10-minute sessions can be performed until tolerance increases
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Precautions and Contraindications
Refer to systems review and physiologic causes of impairment
Consider any injury or disease affecting systems (e.g., patients with DJD could participate in non-weight-bearing exercises)
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Supervision During Exercise
Initial screening and medical evaluation are important to determine if the individual requires supervision.
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Patient-Related Instruction/Education
Patient education (PE) should include “why” & “how” of warm up, training, and cool down phases.
PE on negative signs and symptoms necessitating cease of activity.
PE should include maintenance program upon discharge and importance relating to long-term health maintenance.
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Life Span Guidelines
Children exercising in hot environments should do so at lower intensity.
Age 6 up to & including adults – moderate intensity, 30 minutes, 5–7 days/wk.
Elderly individuals – 30 minutes, 5–7 days/wk with emphasis on minimizing impact on joints (e.g., water exercising, cycling).
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Summary Aerobic capacity or
VO2max is the highest rate of oxygen the body can consume during maximal exercise.
CHOs are the preferred energy source for the body during exercise.
During acute exercise, HR, SV, Q, a-vO2 diff, BP, and RR increase proportionally to the exercise workload.
Benefits of CV endurance training include +ve changes in CV & resp. systems that provide protection from disease & improved psych. well-being and quality of life.
Impaired aerobic capacity can occur – result of primary CV & pulm. disease, diseases of other systems that limit mobility, prolonged bed rest, aging, and sedentary lifestyle.
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Summary (cont.) Areas of PT history requiring
attention are: risk factors for CV disease, social/health habits such as smoking and physical activity, functional ability, and medication history.
Tests and measures include: graded exercise tests, body composition, tests/measures of circulation (e.g., blood pressure).
Exercise prescription should be based on the results of an appropriate exercise test b/f the initiation of a CV program.
CV endurance training can be performed using a variety of exercise modes and training techniques.
Exercise prescription should be based on the individual’s needs and interests, and comorbidities that affect activity performance should be considered.
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Summary (cont.) CV endurance training is
part of a well-balanced exercise program including muscle strengthening, endurance, and flexibility exercises.
Clinician should be able to identify signs and symptoms, intolerance, and contraindications for graded testing.
Supervision requirements are based on patient’s history, risk factors, and abilities.
Educating the patient regarding the specifics of the program(s) will increase the likelihood of patient compliance and adoption of CV exercise as a lifelong habit.