BackgroundPhysical activity (PA) contributes to improving respiratory symptoms. However, validated endpoints are few and there is limited consensus about what is a clinically meaningful improvement for patients. This review summarises the evidence to date on the range of PA endpoints used in chronic obstructive pulmonary disease (COPD), asthma and idiopathic pulmonary fibrosis (IPF) whilst evaluating their appropriateness as endpoints in trials and their relation to patients’ everyday life.MethodsTrials reporting PA endpoints were collected using Citeline's database Trialtrove; this was supplemented by searches in PubMed.ResultsThe daily-patient-reported outcome (PRO)active and clinical visit-PROactive physical activity (D-PPAC & C-PPAC) composite endpoints appeared superior at capturing the full experience of PA in patients with COPD and were responsive to bronchodilator intervention. Time spent in moderate-to-vigorous PA is a recently validated endpoint for IPF that correlates with exercise capacity and quality of life. Step count (SC) appears the best available PA measure for asthma which consistently declines with worse disease status. However, evidence suggests a time lag before significant improvement in SC is seen which may reflect the impact of human behaviour on PA.ConclusionsPA represents a challenging domain to accurately measure. This is the first review evaluating PA measures used specifically within the respiratory field. Whilst PA can be effectively captured using PROactive in patients with COPD, this review highlights the unmet need for novel patient-focused endpoints in asthma and IPF which would offer opportunities to develop efficacious medicines with impact on patients’ therapeutic care and quality of life.