Effects of Neuromuscular Electrical Stimulation on the Activity Levels and Exercise Capacity of Patients with Moderate to Severe COPD

Abstract

Background: Activity levels and exercise capacity are decreased in Chronic Obstructive Pulmonary Disease (COPD) patients. Pulmonary Rehabilitation (PR) programs can be difficult to undertake, particularly for individuals with severe COPD, who experience incapacitating dyspnoea. Neuromuscular electrical stimulation (NMES) is a passive form of muscle stimulation which does not stress the ventilatory system. This study examined the effects of an 8 week NMES programon the activity levels and exercise capacity of individuals with moderate to severe COPD. Methods: This single group cohort control study was performed with 8 participants of mean (SD) age 61.5 (6.16) years with moderate to severe COPD (FEV1/FVC range 0.35-0.79 and FEV1 range 35%-70% predicted). Participants were instructed to carry out NMES training 5 days a week for 8 weeks and were assessed before and after the intervention for activity levels, using a triaxial accelerometer and exercise capacity, asmeasured by the 6 minute walk test (6MWT). Activity levels were expressed as vector magnitude units per min (VMU/min) and percentage of time spent above 500 VMU. Results: Activity levels failed to show statistically significant changes post intervention, but individual changes for VMU/min (p = 0.575) and time spent above 500 VMU (p = 0.327) indicated a trend towards improvement. A statistically and clinically significant improvement for 6MWT distanceswere observed (p = 0.012). No significant correlation between activity levels and exercise capacity was found. conclusions: NMES may be useful adjunct to PR for patients with moderate to severe COPD in order to improve exercise capacity and activity levels.