The Woolcock Institute of Medical Research

Asthma is a complex and variable condition. Although it is often recognised by symptoms such as wheezing, breathlessness, chest tightness and coughing, the underlying mechanisms can differ considerably between individuals. People with similar symptoms may have different patterns of airway dysfunction, experience different disease trajectories and respond differently to treatment.

Understanding this variability is an important challenge for respiratory research. Measuring airway physiology provides a way to investigate how the airways function, how their responses change in disease and how these changes relate to symptoms, lung function and treatment outcomes.

NOT ONE DISEASE

Traditionally, asthma has been characterised by variable respiratory symptoms, airflow limitation and airway hyperresponsiveness. Advances in research have increasingly highlighted that asthma is not a single, uniform disease, but a condition involving multiple interacting clinical, inflammatory, structural and physiological processes.

A recent review published in Respirology, Asthma: From Phenotypes to Endotypes—Beyond Type 2 Inflammation, by Mario Fernando (PhD student at Royal North Shore Hospital and Sydney University) and Woolcock Airway Physiology and Imaging Research Leader Professor Greg King, explores a framework for understanding this complexity. The review considers how asthma can be characterised by endo-phenotypes across three interconnected domains: clinical features, structural and physiological changes, and underlying inflammatory mechanisms.

This broader perspective is important because inflammatory biomarkers alone do not fully explain the range of asthma presentations. While Type 2 (T2) inflammation is relatively well characterised and targeted treatments are available for some patients, other forms of asthma remain more difficult to define and thereby treat.

PHYSIOLOGY’S ROLE

Assessing airway physiology is central to investigating how asthma affects the respiratory system. Measures of airway responsiveness, airflow limitation and small airway dysfunction can help characterise functional changes that may not be fully captured by symptoms or inflammatory biomarkers alone. Detecting these distinct physiologic traits influences the prognosis of an individual’s asthma, and treatment choices.

Structural changes in the airways, collectively described as airway remodelling, are also important. These changes are associated with persistent airflow limitation, airway hyperresponsiveness, declining lung function and disease severity. However, assessing airway remodelling remains challenging, particularly when researchers want to understand how it changes over time. Developing better ways to measure and monitor these changes is an important area for future research.

Combining physiological measurements with clinical information, structural assessment and inflammatory markers may provide a more complete picture of an individual’s disease. This integrated approach could help researchers better distinguish the mechanisms contributing to asthma in different groups of patients.

PRECISION APPROACH

A more detailed understanding of asthma has implications for both research and clinical care. Identifying the mechanisms driving disease in individual patients may ultimately help improve patient classification, inform treatment selection and support the development of new therapeutic approaches.

For airway physiology research, the challenge is to continue refining the tools and methods used to assess airway function, understand structural changes and track disease over time. These advances will be important in connecting measurable changes in the airways with the underlying mechanisms of asthma.

As understanding of asthma evolves, airway physiology will remain an important component of efforts to explain disease complexity and move towards more precise, individualised approaches to respiratory health.

Find out more

• Our Airway Physiology and Imaging research group
• Asthma: From Phenotypes to Endotypes — Beyond Type 2 Inflammation. Respirology. Published online 7 October 2026