Chapter 6 Impaired Aerobic Capacity/Endurance. Physical Activity Exercise Physical Fitness. Cardiorespiratory Endurance The ability of the whole body to sustain prolonged exercise. Physiology of Aerobic Capacity and Endurance. Enables us to perform daily tasks.
Physical Activity Exercise Physical Fitness Cardiorespiratory Endurance The ability of the whole body to sustain prolonged exercise. Physiology of Aerobic Capacity and Endurance Enables us to perform daily tasks
Energy Sources Used During Aerobic Exercise Fat, Carbohydrates, Protein ATP ATP ATP
Fuel Source Selection During Exercise CHO is the preferred fuel source for ATP to supply the body with energy during exercise.
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).
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.
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.
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 Physiologic and Psychological Adaptations to Cardiorespiratory Endurance Training Physiologic Adaptations
Psychologic Benefits of Training Improved • Moods • Depression • Anxiety • Psychological well-being • Perceived quality of life
Heart Muscle Coronary artery disease Pericarditis Congestive heart failure Aneurysms Heart Valves Rheumatic fever Endocarditis Mitral valve prolapse Congenital deformities Causes of Impaired Aerobic Capacity/Rehabilitation Indications
Nervous System Arrythmias e.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
Examination and evaluation of CV and respiratory systems should be included in exam of all clients Tests Identify Presence of disease Establishing a baseline aerobic capacity Measuring change in aerobic capacity Examination/Evaluation of Aerobic Capacity
Patient/Client History • General demographic information • Social/health habits • General health status (physical, role, social functioning, etc.) • Clinical tests (blood cholesterol) • Medications
Examination of other major body systems Skin integrity Muscle strength Joint ROM Balance Gait function Ability to make needs known Communication Affect Cognition Language Learning style Systems Review
Pain in chest, neck, jaws, or areas of ischemia Shortness of breath at rest or with mild exertion Dizziness or syncope Orthopnea Ankle edema Palpitations or tachycardia Intermittent claudication Known heart murmur Unusual fatigue or shortness of breath with usual activities Screening Examination
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.
Anthropometric Characteristics • Hydrostatic – gold standard(requires expensive specialized equipment and patient tolerance) • BMI (body mass index) • Bioelectric impedance • Near-infrared interactance • Skinfold measurements
Circulation • Blood pressure • Heart rate, rhythm, and pattern • Respiratory rate, rhythm, and pattern
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.
Walking Jogging Cross-country skiing Bicycling Rope jumping Rowing Swimming (or water aerobics) Aerobic dance Mode of Intervention Choice of mode depends on: Patients goals and specific physical condition
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.
Dosage – Training Sequence • Initial warm up (5–10 minutes) of large muscle groups (walking, cycling, etc.) • Stretching exercises • More vigorous cardiovascular exercises as prescribed • Cool down with stretching 1&4 2&4 3
Dosage – Frequency • Determined considering patient’s goals • Optimal frequency – 3–5 times per week
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
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
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)
Supervision During Exercise Initial screening and medical evaluation are important to determine if the individual requires supervision.
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.
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).
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. Summary
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. 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. Summary (cont.)