Field exercise testing, especially the 6-min walk test (6MWT), is widely used to assess functional exercise capacity in patients with chronic respiratory diseases. The 6MWT is safe, easy to administer, cost-effective, and represents a natural daily activity. Despite established guidelines, variability in test performance exists and can impact the interpretation of results. The 6MWT is reliable, repeatable, and has been extensively studied in conditions like chronic obstructive pulmonary disease, interstitial lung disease, and pulmonary hypertension. Application is both disease- and context-dependent. Emerging variations include shorter duration tests and telemetric versions, which may continue to expand its clinical utility and accessibility.