Is there any benefit using low-intensity inspiratory and peripheral muscle training in heart failure? A randomized clinical trial

Background Inspiratory and peripheral muscle training improves muscle strength, exercise tolerance, and quality of life in patients with chronic heart failure (HF). However, studies investigating different workloads for these exercise modalities are still lacking. Objective To examine the effects of low and moderate intensities on muscle strength, functional capacity, and quality of life. Design A randomized controlled trial. Methods Thirty-five patients with stable HF (aged >18 years, NYHA II/III, LVEF <40%) were randomized to: non-exercise control group (n = 9), low-intensity training group (LIPRT, n = 13, 15% maximal inspiratory workload, and 0.5 kg of peripheral muscle workload) or moderate-intensity training group (MIPRT, n = 13, 30% maximal inspiratory workload and 50% of one maximum repetition of peripheral muscle workload). The outcomes were: respiratory and peripheral muscle strength, pulmonary function, exercise tolerance by the 6-minute walk test, symptoms based on the NYHA functional class, and quality of life using the Minnesota Living with Heart Failure Questionnaire. Results All groups showed similar quality-of-life improvements. Low and moderate intensities training programs improved inspiratory muscle strength, peripheral muscle strength, and walking distance. However, only moderate intensity improved expiratory muscle strength and NYHA functional class in HF patients. Conclusions The low-intensity inspiratory and peripheral resistance muscle training improved inspiratory and peripheral muscle strength and walking distance, demonstrating that LIPRT is an efficient rehabilitation method for debilitated HF patients. In addition, the moderate-intensity resistance training also improved expiratory muscle strength and NYHA functional class in HF patients.