Chronic obstructive pulmonary disease (COPD) is associated with an increased risk of cardiovascular diseases, particularly coronary artery disease (CAD) [1]. Endothelial dysfunction is a marker of cardiovascular risk [2]; a validated and standardised method to assess endothelial function is flow-mediated dilation (FMD) [3]. Previous studies have shown impaired endothelial function in COPD patients compared to that in healthy subjects [4, 5], with intermediate function between CAD patients and healthy subjects [6]. Endothelial function is positively associated with physical activity and is improved by exercise training in sedentary elderly subjects and cardiac patients [7]. Regarding COPD, this relationship has been reported in retrospective studies, but has not been confirmed in prospective studies [8, 9]. The objective of the present study was to determine whether an 8-week supervised walking-based training programme can improve endothelial function in COPD. 20 COPD (14 males and six females) with forced expiratory volume in 1 s (FEV 1) ⩾30% and ⩽80% predicted [10] who were in a stable clinical condition for ⩾6 weeks were consecutively recruited from the Respiratory Disease Outpatient Clinic, Ferrara University Hospital (Italy). Exclusion criteria were: 1) major cardiovascular diseases (i.e. CAD, uncontrolled hypertension, arrhythmias or heart failure); 2) orthopaedic and neuromuscular exercise limitations; and 3) current structured exercise performance. The Ethics Committee of Ferrara University approved the study (number 140794). Each subject gave informed consent. At baseline (t 0), all patients underwent spirometry and a 6-min walk test (6MWT) [11]. The Charlson Comorbidity Index was calculated and a blood analysis (⩽3 months) was collected. On a separate day, blood pressure was measured in triplicate after 20 min of rest and the FMD test was subsequently performed on the opposite arm. Daily physical activity was monitored for 7 days with the activity and metabolic Holter SenseWear Armband (BodyMedia, Pittsburgh, PA, USA). An 8-week supervised walking-based training programme was described, and the subjects were randomised into two groups: exercise and control. Neither group changed medication; the control group maintained their lifestyle habits, checked with a questionnaire [12]. The exercise group performed a maximal incremental cardiopulmonary exercise test on a cycle ergometer (10-15 W•min −1) to determine the exercise capacity. After 8 weeks (t 1), the subjects repeated all the tests. @ERSpublications Supervised exercise training is key to health improvement in chronic obstructive pulmonary disease patients https://bit.ly/2AdfKvb Cite this article as: Merlo C, Bernardi E, Bellotti F, et al. Supervised exercise training improves endothelial function in COPD patients: a method to reduce cardiovascular risk?