Speaker's Highlight

• Don Sin University of British Columbia, St. Paul Hospital (Canada)
  Kenneth R. Chapman Toronto General Hospital Research Institute (Canada)
• Parameswaran Nair McMaster University (Canada)
  Carolyn Calfee UCSF (U.S.A.)
• Gregory P. Downey University of Colorado School of Medicine (U.S.A.)
  David A. Schwartz University of Colorado School of Medicine (U.S.A.)
• Neil Schluger Tuberculosis Control Branch, California Department of Public Health (U.S.A.)
  Nick Kim Critical Care & Sleep Medicine, University of California San Diego (U.S.A.)
• Nicola Hananiah Baylor College of Medicine (U.S.A.)
  Jae-Joon Yim Seoul National University College of Medicine (Republic of Korea)
• Koichiro Asano Tokai University School of Medicine (Japan)
  Diahn-Warng Perng Taipei Veterans General Hospital (Taiwan)
• Konstantinos Kostikas University of Ioannina (Greece)
  Karin Klooster University Medical Center Groningen (Kingdom of the Netherlands)

• Exercise Testing in Interstitial Lung Disease Care

  Interstitial lung disease (ILD) includes a broad group of conditions that scar, inflame or otherwise damage the lung tissue. As the disease progresses, patients may experience exertional breathlessness, reduced exercise tolerance and fatigue before resting oxygen levels become abnormal. Exercise testing helps clinicians measure this functional burden in a controlled and clinically meaningful way.

  For respiratory teams working across Australia, testing can support diagnosis, prognosis, pulmonary rehabilitation and decisions about oxygen therapy or referral for advanced care. It also provides information that spirometry alone cannot capture, particularly when a patient reports severe breathlessness but has only modest changes in resting lung function.

  Why Exercise Testing Matters

  Many people with ILD maintain acceptable oxygen saturation while seated yet develop significant desaturation during walking or cycling. Exercise testing places a safe, reproducible demand on the cardiopulmonary system and shows how effectively the lungs deliver oxygen during activity.

  The six-minute walk test (6MWT) is widely used because it is practical, inexpensive and easy to repeat. Walking distance, heart rate, symptoms and oxygen saturation can be recorded together. A reduced distance or a meaningful fall in saturation may indicate limited functional reserve, although results must be interpreted alongside age, height, comorbidities, musculoskeletal health and usual activity levels.

  More detailed assessment may be appropriate when the clinical picture is unclear. Cardiopulmonary exercise testing (CPET) measures ventilation, oxygen consumption and carbon dioxide production while workload increases. It can help distinguish ventilatory limitation from cardiac disease, deconditioning or dysfunctional breathing.

  Selecting A Suitable Test

  The choice of assessment should reflect the clinical question. A corridor walk may be sufficient for monitoring a person with established pulmonary fibrosis, while an incremental shuttle walk test can provide a more standardised progressive challenge. A cycle-based test may be preferable for patients with painful joints, balance concerns or limited walking ability.

  Standardisation is essential. Staff should document the course length, encouragement, oxygen flow, walking aids and rest periods. The same protocol should be used when possible so that changes over time are more likely to reflect the disease or its treatment rather than differences in test conditions.

  Safety screening is equally important. Clinicians should review cardiovascular history, recent exacerbations, syncope, severe pulmonary hypertension and musculoskeletal limitations. Testing should occur where trained staff, emergency equipment and an appropriate escalation pathway are available.

  Interpreting Oxygen And Exercise Responses

  A fall in oxygen saturation during exertion can provide important evidence of gas-transfer impairment. However, pulse oximetry has limitations, particularly with cold fingers, motion, poor peripheral circulation, nail products or darker skin pigmentation. A questionable reading should be checked rather than treated as definitive.

  Distance alone should not determine clinical decisions. A patient may walk a similar distance but report greater dyspnoea, require more oxygen or show a faster heart-rate response. Conversely, a stable walk distance with lower symptoms may indicate a meaningful improvement in conditioning or symptom management.

  CPET can add further detail through measurements such as peak oxygen uptake, ventilatory efficiency and the breathing reserve. These results may help identify pulmonary vascular disease or cardiac limitation, but interpretation requires expertise and should be integrated with high-resolution CT, pulmonary function tests and echocardiography where indicated.

  Linking Results With Treatment

  Exercise testing can guide pulmonary rehabilitation by identifying the intensity a patient can tolerate and by tracking progress over several weeks. Programs commonly combine aerobic activity, resistance training, breathing strategies and education. A test result can make the benefits of rehabilitation more tangible for patients who feel that breathlessness has made activity unsafe.

  Testing may also inform ambulatory oxygen assessment. Oxygen needs during a supervised walk should be evaluated according to local protocols and the person’s usual activities, rather than inferred from resting saturation alone. A prescription should account for equipment weight, flow requirements and whether the patient can manage the device independently.

  In Australia, this practical detail matters when patients travel between metropolitan and regional services or rely on portable concentrators and cylinders. Someone living in Western Sydney, Melbourne or Brisbane may have access to hospital-based rehabilitation, while a person in rural New South Wales or regional Queensland may need telehealth support, local physiotherapy or a longer journey to specialist care.

  Making Assessment Practical In Australian Services

  Respiratory clinics connected with major teaching hospitals in Sydney, Melbourne, Perth and Adelaide may offer CPET and specialist ILD review, but access is less consistent outside capital cities. Test selection should therefore consider available expertise, travel burden and the likelihood that the result will change management.

  Clinicians should explain the purpose of testing in clear language and allow time for questions about breathlessness, oxygen and safety. This is especially relevant for Aboriginal and Torres Strait Islander patients and for people whose first language is not English. Cultural safety, interpreters and attention to family involvement can improve participation and the usefulness of follow-up.

  Useful practice points include:

  • Use the same validated walking protocol when monitoring change over time.
  • Record oxygen delivery, symptoms, heart rate, saturation and walking aids.
  • Confirm unexpected oximetry results with repeat measurement or clinical review.
  • Match exercise advice to local rehabilitation access, transport and equipment options.
  • Reassess when there is a significant change in symptoms, lung function or treatment.

  Keeping Findings In Long-Term Perspective

  Interstitial lung disease often changes gradually, so a single exercise test should be viewed as one point in a longer clinical record. Serial results can show whether functional decline is accelerating, whether antifibrotic therapy is stabilising performance, or whether rehabilitation is improving confidence and endurance even when lung volumes remain unchanged.

  Results should be discussed with the wider care team, including respiratory physicians, physiotherapists, nurses, occupational therapists and primary care clinicians. When appropriate, they can support conversations about advance care planning, transplant referral, symptom control and the equipment needed for daily life.

  The most useful exercise assessment is safe, repeatable and connected to a clear clinical decision. For people with ILD, the key message is that how the lungs perform during activity can reveal important disease burden long before resting measurements tell the whole story.

  Richard Russell Nuffield Department of Clinical Medicine, University of Oxford (United Kingdom)
• Mona Bafadhel King’s College London (United Kingdom)
  David Jackson Guy’s and St Thomas’ Hospital, King’s College London (United Kingdom)
• James Chalmers University of Dundee (United Kingdom)
  David Price University of Aberdeen (United Kingdom)