Cardio Respiratory Aspects Of Functional Rehab

Integrating heart and lung science into every stage of movement-based recovery, from the bedside to the community

Intermediate · 12 chapters · 144 MCQs · 144 flashcards · Illustrated

This course equips physiotherapists to assess, prescribe and progress cardiorespiratory-informed rehabilitation across acute, subacute and community settings. You will move from applied physiology through objective assessment and evidence-based interventions, then into complex and special populations, and finish by translating gains into measurable functional outcomes. Every chapter is built around clinical reasoning, practical decision-making and safe, patient-centred application.

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What you'll learn

  1. Chapter 1: Cardiorespiratory Anatomy and Physiology Essentials for Functional Rehabilitation

    Functional rehabilitation depends on the body's ability to deliver oxygen to working tissues and remove metabolic waste. Limb strength, balance, and gait all fail when the cardiorespiratory system cannot meet demand.

  2. Chapter 2: Oxygen Transport, Exercise Physiology and the Effects of Immobility and Deconditioning

    This chapter explains how oxygen moves from the atmosphere to the working muscle, how the body responds to exercise, and why even short periods of immobility produce measurable cardiorespiratory decline.

  3. Chapter 3: Pathophysiology of Common Cardiac, Pulmonary and Mixed Conditions Encountered in Rehab

    Heart failure (HF) is a clinical syndrome caused by structural or functional impairment of ventricular filling or ejection.

  4. Chapter 4: Clinical Assessment: History, Observation, Auscultation, Vital Signs and Red-Flag Screening

  5. Chapter 5: Investigations and Outcome Measures: Imaging, Spirometry, ABGs, ECG and Functional Capacity Tests

    Cardiorespiratory investigations exist to answer four questions: is the airway obstructed or restricted, is gas exchange adequate, is the heart responding safely to load, and how much work can the patient tolerate? Each test addresses a…

  6. Chapter 6: Clinical Reasoning and Exercise Prescription: Risk Stratification, Dosage, Monitoring and Safety

  7. Chapter 7: Airway Clearance, Breathing Retraining and Ventilatory Muscle Training Techniques

    Effective airway clearance depends on three integrated mechanisms: mucociliary transport, cough clearance, and adequate ventilatory mechanics. Failure of any one predisposes to secretion retention.

  8. Chapter 8: Aerobic, Resistance and Interval Training for Cardiac and Pulmonary Populations

  9. Chapter 9: Oxygen Therapy, Non-Invasive Ventilation and Mobilisation of the Acute and Critically Ill Patient

  10. Chapter 10: Special Situations: Post-Surgical, Neurological, Frail Older Adult, Paediatric and Post-COVID Considerations

    Standard cardiorespiratory rehabilitation protocols assume a relatively stable patient with predictable physiology. Many patients on a physiotherapy caseload do not fit that model.

  11. Chapter 11: Energy Conservation, Dyspnoea Management and Integrating Cardiorespiratory Training into Functional Tasks

    Dyspnoea is a subjective experience of breathing discomfort, arising from a mismatch between the central motor command to breathe and the sensory feedback the brain receives from the respiratory system (the "neuromechanical dissociation"…

  12. Chapter 12: Long-Term Outcomes: Cardiopulmonary Rehabilitation Programme Design, Self-Management and Return to Participation

Free chapter

Chapter 1: Cardiorespiratory Anatomy and Physiology Essentials for Functional Rehabilitation

Chapter Overview

Functional rehabilitation depends on the body's ability to deliver oxygen to working tissues and remove metabolic waste. Limb strength, balance, and gait all fail when the cardiorespiratory system cannot meet demand. This chapter reviews the physiology that underpins exercise tolerance, describes how dysfunction presents clinically, and outlines assessment and staged management for physiotherapists.

Core Physiology: Oxygen Transport

Oxygen uptake (VO₂) is governed by the Fick equation: VO₂ = cardiac output × (arterial − mixed venous oxygen content difference). Cardiac output equals heart rate multiplied by stroke volume. At rest, cardiac output is approximately 5 L/min. During maximal exercise in a fit adult it may exceed 20 L/min. Stroke volume typically plateaus at moderate intensities, so heart rate drives most of the early increase in output.

Hemoglobin carries roughly 1.34 mL O₂ per gram when fully saturated. Anaemia therefore reduces oxygen content without any primary cardiac or lung disease, and it must be considered whenever exercise tolerance is unexpectedly poor.

Respiratory Mechanics

The diaphragm is the primary inspiratory muscle, supported by the external intercostals, scalenes, and sternocleidomastoid during increased demand. Expiration is passive at rest and becomes active through the abdominal muscles and internal intercostals during exercise. Ventilation rises from roughly 6 L/min at rest to over 100 L/min in maximal exertion in healthy adults.

Ventilation-perfusion matching determines gas exchange efficiency. Dead space ventilation (V_D/V_T) normally falls to about 0.2–0.3 with exercise. Its failure to fall, or a rising ventilatory equivalent for CO₂ (VE/VCO₂), signals inefficient gas exchange and is an important prognostic marker in heart failure.

Autonomic and Exercise Responses

Exercise produces a rapid vagal withdrawal followed by sympathetic activation. Heart rate and contractility increase, peripheral vasoconstriction redistributes blood toward working muscle, and the baroreflex maintains arterial pressure. Systolic blood pressure should rise progressively with workload, typically to 160–200 mmHg in healthy adults at peak effort. Diastolic pressure should remain stable or fall slightly.

Heart rate recovery (HRR) reflects parasympathetic reactivation. A fall of less than 12 bpm at one minute after peak exercise is associated with increased mortality (Cole et al., 1999).

Clinical Presentation of Dysfunction

Cardiorespiratory limitation usually presents as one or more of the following:

Cardiorespiratory limitation often shows as dyspnoea out of proportion to the workload, graded with the mMRC scale (0–4) or Borg CR10.

Cardiorespiratory limitation often shows as dyspnoea out of proportion to the workload, graded with the mMRC scale (0–4) or Borg CR10.

  • Dyspnoea out of proportion to workload, graded with the Modified Medical Research Council (mMRC) scale (0–4) or Borg CR10.
  • Exercise-induced desaturation (SpO₂ falling by 4% or more, or below 88%).
  • Early fatigue with preserved limb strength, suggesting a central or ventilatory limit.
  • Chest pain, presyncope, or palpitations during activity, which require urgent screening.
  • Orthostatic symptoms, defined by a drop of at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing (Freeman et al., 2011).

Typical conditions include chronic obstructive pulmonary disease (COPD), heart failure, post-myocardial infarction, post-cardiac surgery, pulmonary embolism, deconditioning after critical illness, and long COVID.

Assessment

Resting Vital Signs and Normative Values

  • Heart rate: 60–100 bpm
  • Blood pressure: normal below 120/80 mmHg; stage 1 hypertension 130–139/80–89 mmHg; stage 2 at or above 140/90 mmHg (Whelton et al., 2018)
  • Respiratory rate: 12–20 breaths/min
  • SpO₂: 95–100% on room air

Estimated maximum heart rate is calculated as 208 − (0.7 × age) (Tanaka et al., 2001), which is more accurate than the older 220 − age formula.

Functional Capacity Tests

  • 6-Minute Walk Test (6MWT): Standard distance is measured on a 30 m course. Healthy adults typically walk 400–700 m. A change of 25–30 m is considered the minimal clinically important difference in COPD (Holland et al., 2014). Distances below 350 m are associated with worse outcomes in chronic disease.
  • 30-Second Chair Stand (Rikli & Jones, 1999): Below-average scores for women aged 60–64 are fewer than 12 stands, and for men aged 60–64 fewer than 14.
  • Two-Minute Step Test: Counts steps with knee height target; compare against HR and SpO₂ response.
  • Incremental Shuttle Walk Test: Used when sensitivity to change is needed.
  • Cardiopulmonary Exercise Testing (CPET): Gold standard. Key outputs include peak VO₂ (ml/kg/min), anaerobic threshold, VE/VCO₂ slope (above 34 is poor prognosis in heart failure), and oxygen pulse.

Respiratory and Cardiac Measures

  • Spirometry: Obstruction is defined as post-bronchodilator FEV₁/FVC below 0.70. GOLD grades severity by FEV₁ percent predicted: GOLD 1 at or above 80%, GOLD 2 at 50–79%, GOLD 3 at 30–49%, GOLD 4 below 30% (GOLD, 2024).
  • Maximal inspiratory pressure (MIP): Measured against predicted values, with reduced values indicating respiratory muscle weakness.
  • Heart failure classification: NYHA I–IV, and ejection fraction (HFrEF ≤40%; HFpEF ≥50%).

Management: Staged Protocols and Dosage

Exercise prescription should follow ACSM principles of frequency, intensity, time, and type (FITT), within a safety framework (Liguori et al., 2021).

Stage 1: Acute or Early Recovery (Days to Weeks)

  • Goal: Safe mobilisation, prevention of deconditioning.
  • Intensity: 3–4 on the Borg CR10 scale, or 11–12 on the Borg 6–20 scale; talk test passed.
  • Duration: 5–10 minutes, 2–3 bouts per day.
  • Mode: Sit-to-stand, walking, bed-based limb exercise, and breathing control (pursed-lip breathing).

Stage 2: Progressive Aerobic Conditioning (Weeks 2–8)

  • Intensity: 40–59% heart rate reserve (HRR) or RPE 11–13, progressing to 60–75% HRR.
  • Duration: Increase by 1–2 minutes per session to a target of 20–30 minutes.
  • Frequency: 3–5 days/week, targeting 150 minutes per week of moderate activity.
  • Mode: Interval walking or cycling, with work-to-rest ratios such as 1:1 for low-capacity patients.

Stage 2 builds to 20–30 minutes at 40–59% heart rate reserve or RPE 11–13. Low-capacity patients can use interval cycling at a 1:1 work-to-rest ratio.

Stage 2 builds to 20–30 minutes at 40–59% heart rate reserve or RPE 11–13. Low-capacity patients can use interval cycling at a 1:1 work-to-rest ratio.

Stage 3: Strength and Functional Integration (Weeks 6–12)

  • Resistance training: 2–3 days/week, 8–12 repetitions at 40–70% of 1-repetition maximum, 1–3 sets.
  • Functional circuits: stair climbing, carrying, and transfers at target heart rate.
  • Respiratory muscle training may be added for patients with reduced MIP, at 30% of maximal inspiratory pressure initially, progressing as tolerated.

Stage 4: Maintenance and Self-Management

  • Transition to home programs, community exercise, or cardiac or pulmonary rehabilitation Phase IV.
  • Reassess the 6MWT and sit-to-stand at 6–12 weeks to document change.

Stop Criteria During Exercise

  • Chest pain or pressure
  • Systolic pressure falling by 10 mmHg or more despite increasing workload
  • SpO₂ below 88%
  • Dizziness, confusion, or pallor
  • Abnormal arrhythmia or symptoms out of proportion to effort

Contraindications

  • Absolute: Unstable angina, uncontrolled symptomatic arrhythmia, decompensated heart failure, acute myocarditis or pericarditis, severe symptomatic aortic stenosis, recent (less than 48 hours) suspected pulmonary embolism.
  • Relative: Resting SBP above 200 mmHg or DBP above 110 mmHg, significant electrolyte abnormality, uncontrolled diabetes, recent syncope.

Clinical Pearls

  • Always check the medication list. Beta-blockers blunt heart rate response, so use RPE or the talk test rather than HR targets.
  • Measure SpO₂ at rest, during, and after activity. Desaturation below 88% during a 6MWT is a clinical trigger for supplemental oxygen assessment.
  • Use HRR, not percentage of predicted maximum, when beta-blockers or pacing are present.
  • Watch for orthostatic hypotension in patients with heart failure, autonomic neuropathy, or after prolonged bed rest. Test lying, sitting, and standing blood pressure before standing exercise.
  • Dyspnoea should guide progression, not just heart rate. A Borg dyspnoea rating of 3–4 is a useful target in pulmonary conditions.
  • Re-screen if symptoms change. New chest pain, unexplained weight gain, or rising oedema should prompt referral before continuing.

Summary

Cardiorespiratory function determines how effectively the body meets the metabolic demands of functional movement. Oxygen transport depends on cardiac output, hemoglobin, ventilation, and gas exchange, all coordinated by autonomic control. Dysfunction presents as disproportionate dyspnoea, desaturation, early fatigue, or abnormal blood pressure response. Physiotherapists should use validated measures, including the 6MWT, 30-second chair stand, spirometry, and HRR, to establish baselines and track progress. Staged exercise programmes, guided by the FITT principles, safety thresholds, and clear stop criteria, allow patients to progress from early mobilisation to independent functional activity. Recognising contraindications and red flags is essential to safe practice.

References

  1. Liguori G, Feito Y, Fountaine CJ, Roy B, eds. ACSM's Guidelines for Exercise Testing and Prescription. 11th ed. Philadelphia: Wolters Kluwer; 2021.
  2. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Hypertension. 2018;71(6):e13–e115.
  3. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global Strategy for the Diagnosis, Management, and Prevention of COPD. 2024 Report. Available at: goldcopd.org.
  4. Holland AE, Spruit MA, Troosters T, et al. An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease. Eur Respir J. 2014;44(6):1428–1446.
  5. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS. Heart-rate recovery immediately after exercise as a predictor of mortality. N Engl J Med. 1999;341(18):1351–1357.
  6. Rikli RE, Jones CJ. Development and validation of a functional fitness test for community-residing older adults. J Aging Phys Act. 1999;7(2):129–161.
  7. Freeman R, Wieling W, Axelrod FB, et al. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011;21(2):69–72.
  8. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153–156.

The other 11 chapters, all 144 MCQs and the flashcards are in the PhysioAI app.

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Practice questions

5 sample MCQs from this course. Tap a question to see the answer.

  1. A 67-year-old man with heart failure with reduced ejection fraction attends a rehabilitation clinic. He reports breathlessness after climbing one flight of stairs and has to stop to recover. Observation shows shallow chest-dominant breathing at rest.

    1. Which muscle is the primary inspiratory muscle during quiet breathing?

    • A. Diaphragm
    • B. Rectus abdominis
    • C. Latissimus dorsi
    • D. Pectoralis minor
    Show answer

    Answer: A. The diaphragm contracts and flattens during quiet inspiration, producing most of the increase in thoracic volume. Accessory muscles such as the scalenes and sternocleidomastoid are recruited mainly when breathing demand rises or work of breathing increases.

  2. A 62-year-old man is referred for a graded walking test after a myocardial infarction 6 weeks ago. He reports breathlessness on climbing one flight of stairs and has been avoiding household chores. His resting arterial oxygen saturation is 97%.

    2. Which equation, based on the Fick principle, best describes his whole-body oxygen uptake during the test?

    • A. VO2 = cardiac output × (arterial minus mixed venous oxygen content)
    • B. VO2 = heart rate × arterial oxygen saturation
    • C. VO2 = haemoglobin concentration × SpO2 only
    • D. VO2 = minute ventilation ÷ 2
    Show answer

    Answer: A. The Fick principle states that oxygen consumption equals cardiac output multiplied by the arteriovenous oxygen content difference. Heart rate, saturation, or ventilation alone do not describe total oxygen uptake.

  3. A 68-year-old man has a long-standing history of heart failure with reduced ejection fraction (EF 30%). He becomes breathless after climbing one flight of stairs, needs three pillows to sleep, and has bilateral ankle oedema.

    3. Which mechanism best explains his exertional dyspnoea?

    • A. Reduced cardiac output with elevated pulmonary venous pressure during exertion
    • B. Increased airway resistance from bronchoconstriction
    • C. Reduced alveolar surface area from emphysematous destruction
    • D. Increased haemoglobin affinity for oxygen
    Show answer

    Answer: A. In heart failure with reduced ejection fraction, the failing ventricle cannot raise cardiac output adequately during exertion, and backward transmission of pressure raises pulmonary venous and capillary pressures. This fluid shift into the lung interstitium triggers breathlessness, orthopnoea and exercise intolerance.

  4. A 58-year-old man with a 40 pack-year smoking history reports breathlessness when climbing one flight of stairs and a productive cough most mornings. Spirometry shows FEV1 56% predicted and an FEV1/FVC ratio of 0.62 after bronchodilator. He is referred for an exercise prescription.

    4. Which spirometric pattern is most consistent with these results?

    • A. Obstructive ventilatory defect
    • B. Restrictive ventilatory defect
    • C. Normal spirometry
    • D. Fixed upper airway obstruction
    Show answer

    Answer: A. A reduced FEV1/FVC ratio (below about 0.70) with a reduced FEV1 indicates airflow limitation, which is the hallmark of an obstructive pattern. Restrictive defects show a normal or raised ratio with reduced FVC, so they do not fit this profile.

  5. A 58-year-old woman with bronchiectasis reports a daily productive cough with thick green sputum and breathlessness on climbing stairs. She lives alone and wants a self-management routine she can perform without assistance.

    5. Which airway clearance approach is generally recommended first for her independent self-management?

    • A. Active cycle of breathing technique, including breathing control, thoracic expansion and forced expiration
    • B. Prolonged supine rest with no airway clearance performed
    • C. Maximal voluntary ventilation performed once daily
    • D. Routine high-flow oxygen at 15 L/min to loosen sputum
    Show answer

    Answer: A. The active cycle of breathing technique is a flexible, self-directed sequence of breathing control, thoracic expansion and forced expiration that can be used independently. Passive rest, maximal ventilation and high-flow oxygen do not clear secretions effectively.

Flashcards

  • What are the four chambers of the heart, and which two are the atria?

    The heart has two atria (right and left), which receive blood returning to the heart, and two ventricles (right and left), which pump blood out. The right side handles deoxygenated blood to the lungs, and the left side handles oxygenated blood to the body.

  • What is Hüfner's constant, and how much oxygen can 1 g of fully saturated haemoglobin carry?

    Hüfner's constant is approximately 1.34 mL of O2 per gram of haemoglobin when fully saturated. It is used in the arterial oxygen content calculation. Only a small fraction of oxygen travels dissolved in plasma.

  • What is the earliest event in the development of atherosclerotic plaque?

    Endothelial injury or dysfunction allows LDL cholesterol to accumulate and oxidize within the arterial intima. Monocytes are recruited and transform into macrophages that engulf lipid to form foam cells. These fatty streaks can progress to fibrous plaques over time.

  • What are the typical normal ABG reference ranges for pH, PaCO2, HCO3-, and PaO2 in an adult at rest on room air?

    Normal arterial pH is 7.35 to 7.45, PaCO2 is 35 to 45 mmHg, and HCO3- is 22 to 26 mEq/L. PaO2 is usually 80 to 100 mmHg on room air, and it declines with age.

  • What is the main purpose of airway clearance techniques in cardiorespiratory physiotherapy?

    Airway clearance techniques aim to mobilise and remove excess secretions from the airways to improve gas exchange, reduce work of breathing, and lower the risk of infection or atelectasis. They are used when a patient cannot clear secretions effectively, for example in COPD, bronchiectasis, cystic fibrosis, or post-operatively. The choice of technique depends on the patient's secretion load, cooperation, and clinical condition.

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