14.3 Exercise Prescription for Cardiorespiratory Populations

Quick Answer: Prescribe CR exercise with FITT + safety stops. Use 6MWT/field tests to inform function and walking dose—never invent universal metre cut-offs. Titrate with SpO2 trends + symptoms + RPE (especially if beta-blocked). Maintain gains in community programs. Never change oxygen flow yourself; if the person still desaturates/distresses on prescribed O2, stop and escalate.

Exercise is the most potent non-pharmacological intervention physiotherapists offer people with chronic cardiorespiratory disease—provided intensity, mode, and monitoring are safe. This section integrates field test concepts, SpO2-guided training, RPE, community programs, and oxygen-user rules that appear across COPD, ILD, CF (stable), post-acute recovery, and mixed cardiac–pulmonary cases on the APC Written Assessment.

Principles of Exercise Prescription in CR Populations

Use the familiar FITT framework, adapted to respiratory limits:

• Frequency: commonly most days for aerobic activity in PR-style care (individualised); resistance 2–3 days/week when included.
• Intensity: guided by symptoms, RPE/dyspnoea scales, percentage of field-test performance, interval vs continuous structure, and SpO2 response within medical targets—not ego or fixed metabolic equations alone.
• Time: build duration gradually; intervals help when continuous walking causes intolerable dyspnoea or desaturation.
• Type: walking (most functional), cycle ergometry (lower weight-bearing, useful with MSK limits), resistance training, balance as needed, and flexibility.

Always screen for absolute stop reasons during sessions: chest pain of ischaemic character, new arrhythmia symptoms, syncope/near-syncope, severe intolerable dyspnoea not settling with rest, signs of respiratory failure, neurological change, or SpO2/clinical deterioration outside agreed parameters.

Progress after illness/exacerbation by rebuilding from a lower baseline, not by assuming pre-illness PR numbers still apply. Multimorbidity (HF + COPD, ILD + pulmonary hypertension themes) lowers ceilings and tightens monitoring—link cardiac safety chapter logic when chest pain or congestion appears.

Field Test Concepts: 6MWT Awareness (Without Invented Cut-Offs)

The 6-minute walk test (6MWT) is a common field test of functional exercise capacity. It measures the distance walked in six minutes on a standardised course, with standardised instructions, permitted rests, and monitoring of symptoms and often SpO2/HR.

What you should reason about on APC

• Purpose: baseline function, response to PR, and practical walking prescription (e.g. training at a pace related to average 6MWT speed, or using interval schemes derived from test behaviour)—exact local formulas vary; conceptual understanding matters more than memorising unpublished numbers.
• Standardisation matters: course length, encouragement script, supplemental oxygen use (same as usual prescription), footwear, and timing relative to bronchodilators can change distance. Comparing non-standard tests as if identical is flawed.
• Interpretation is contextual: distance, nadir SpO2, RPE, reason for stops, and gait aids all inform clinical meaning. A single metre value without context is incomplete.
• Do not invent universal cut-offs as if every patient below X metres “fails physio” or above Y metres needs no rehab. Prognostic research thresholds exist in literature, but APC-style safety answers rarely hinge on an obscure number you invent under stress. Prefer principles: desaturation pattern, symptom limit, and change from the patient’s own baseline.

Other field/submaximal concepts you may see: incremental shuttle walk tests, sit-to-stand counts, and timed walking in corridors when formal labs are unavailable. Same rule: know why the test is used and how results guide training and safety, not memorise every reference equation.

Using test results to prescribe (conceptual)

Safety during testing mirrors training: stop for ACS symptoms, syncope, severe distress, or protocol-defined SpO2/clinical limits. A field test is not a licence to ignore red flags “because we need the metres for the form.”

SpO2-Guided Exercise

Pulse oximetry supports safe titration in COPD, ILD, CF, and post-acute respiratory illness when used as an adjunct to clinical assessment—not a sole decision-maker.

Practical rules

1. Know the patient-specific target range from medical orders or documented care plans when available (e.g. some COPD patients have target ranges that differ from healthy young adult norms).
2. Measure resting baseline before exercise when monitoring is indicated.
3. Watch trend during activity: progressive desaturation with distress differs from a minor brief dip that recovers quickly with rest in a known pattern—interpret with symptoms and cognition.
4. Respond by reducing intensity, adding rest intervals, checking inhaler/oxygen setup as prescribed, and stopping/escalating if severe desaturation, cyanosis, confusion, or chest pain occurs.
5. Poor signal quality (cold hands, movement artefact, nail polish, poor perfusion) can mislead—verify clinically.

Hyperoxia caution: in some patients at risk of CO2 retention, uncontrolled high oxygen can be harmful. This is why you do not freely crank oxygen. Work with prescribed targets and medical guidance.

RPE and Symptom Scales

Rating of perceived exertion (RPE) (Borg 6–20 or CR-10) and dyspnoea scales allow intensity regulation when:

• Beta-blockers blunt HR rise
• Arrhythmias or paced rhythms complicate HR targets
• Patients struggle with abstract “percentage of maximum” language
• Interval training needs simple session-to-session communication

Teach anchors: light, moderate, somewhat hard—linked to talk test concepts (can speak in sentences vs only words). Combine RPE with SpO2 and stop criteria rather than using RPE alone in high-risk desaturators. Rising RPE at the same external work across sessions can signal infection, anaemia, cardiac decompensation, or overreaching—investigate rather than only “push harder.”

Community Cardiorespiratory and Maintenance Programs

After formal PR, maintenance activity preserves gains. Community options include supervised maintenance classes, pulmonary rehab graduate groups, walking groups, home programs with follow-up, and telehealth check-ins where available—highly relevant across metropolitan and rural Australian services.

Physiotherapy reasoning for community CR

• Re-screen for new cardiac/respiratory instability before progressions
• Keep exercise functional and enjoyable to support adherence
• Maintain education refreshers: exacerbation action plans, inhaler technique review pathways, smoking cessation supports
• Adapt for multimorbidity, frailty, and equipment access in rural/remote Australian settings
• Document goals and when to return to medical or specialist PR review
• Plan practical logistics: oxygen cylinders for outings, weather/air-quality modifications, transport, and carer support

Community does not mean unsupervised maximal testing of unstable patients in a park without a plan. It also does not mean “PR finished = disease cured—stop all structured activity.”

Oxygen Users: Hard Safety Rule

People may use long-term oxygen therapy (LTOT), ambulatory oxygen, or nocturnal support. Physiotherapy implications:

• Do not adjust oxygen flow rate, FiO2, or device mode without medical orders.
• Ensure tubing safety during mobility (trip hazard, disconnection).
• Confirm the person uses oxygen as prescribed during exertion if that is the order—underuse can cause unsafe desaturation; overuse outside orders is also unsafe.
• If the patient cannot exercise within prescribed oxygen and still has unacceptable desaturation or distress, stop and escalate medically—do not “fix” the problem with unofficial higher flow.
• Coordinate cylinder/concentrator logistics for community outings as part of practical rehab planning.
• Watch for skin/pressure issues at nasal cannula sites and educate on safe home oxygen behaviours (no smoking near oxygen—fire risk education within team pathways).

This rule mirrors cardiac telemetry and medication boundaries: physios optimise movement within medical parameters.

Putting Prescription Together: Worked Reasoning Pattern

1. Stability check — not in exacerbation; vitals acceptable; oxygen prescription clear; rescue meds available if asthma/COPD plan requires.
2. Choose mode — walking if goal is community mobility; bike if orthopaedic pain limits walking.
3. Set intensity — start from recent field test behaviour, RPE target zone, and SpO2 limits; prefer intervals if continuous fails.
4. Monitor — symptoms, RPE, SpO2/HR as indicated; stop criteria rehearsed with the patient.
5. Progress — duration first often, then intensity, then complexity (terrain, dual-task), reassess after illness.
6. Educate — home plan, when to pause exercise and seek care (sputum change, fever, chest pain, syncope).
7. Review — outcome measures and shared goals with the person and team.

Example reasoning: stable COPD graduate of PR walks 360 m on standardised 6MWT with nadir SpO2 90% on prescribed ambulatory O2, RPE moderate, stops twice for dyspnoea. Community plan might use interval walking near comfortable test pace, strength twice weekly, SpO2 checks when available, and clear advice to seek review for sputum/fever/rest dyspnoea—not “must hit 500 m or physio has failed.”

APC Traps to Avoid

• Quoting a made-up 6MWT metre cut-off as the sole reason to withhold all rehab
• Ignoring desaturation because the patient “wants to keep going”
• Increasing oxygen independently to chase a prettier SpO2 number
• Using HR-only targets in beta-blocked patients without RPE/symptoms
• Equating PR with ACT only or education only
• Forgetting resistance training when peripheral weakness limits walking
• Treating maintenance as optional fluff rather than part of chronic disease care
• Comparing non-standard corridor walks as if they were identical 6MWTs

Competency Links

Exercise prescription demonstrates assessment/planning, risk management, collaborative practice (PR teams, EP, medical oxygen prescribers), and person-centred goal setting. Cultural safety applies when explaining stop rules, oxygen safety, and smoking near oxygen without humiliation. Document intensity anchors, SpO2 responses, assistance, and education so the next clinician can continue safely.

Closing Exam Anchor

Prescribe exercise like a safety-minded clinician: field tests inform but do not dictate with fictional cut-offs; SpO2 and RPE guide real-time titration; community programs maintain gains; oxygen stays as prescribed. If the person deteriorates or targets cannot be met safely, escalate—exercise is powerful only when it is controlled.