Classification(s): Exercise Training; Clinical Medicine/Surgical Interventions
Introduction: B-type natriuretic peptide (BNP), a cardiac hormone produced and secreted by the ventricles in response to increased wall stress, has been shown to be elevated in proportion to the severity of heart failure (HF).
Purpose: The aim of this preliminary study was to assess the effect of an exercise training program on plasma BNP levels over time.
Design: This is a descriptive, prospective pilot study.
Methods: Forty-two subjects with HF were recruited to participate in the HEART CAMP study and randomized into an Attention Control group (CON) or an Exercise intervention group (EX). Plasma BNP was obtained on all subjects at baseline. The EX group (12 men/10 women) attended cardiac rehabilitation for 3 weeks to rule out any significant arrhythmias or hemodynamic abnormalities associated with exercising. The EX subjects then attended the hospital fitness center where they were instructed in an individualized training program consisting of aerobic and resistance exercises. Participants continued their independent exercise program and attended one group education session a week. At 12 weeks, plasma BNP levels were obtained. Subjects continued their training programs for an additional 12 weeks independently. At 24 weeks, plasma BNP levels were again obtained. Subjects randomized to the CON group (12 men/8 women) attended weekly group meetings for the first 12 weeks and did not participate in any regular exercise programs. CON group subjects also had plasma BNP levels measured at 12 and 24 weeks. Complete data sets were obtained on 39 subjects for analysis. For this preliminary study, groups were compared at baseline and descriptive statistics were performed to assess trends in BNP levels.
Results: At baseline, there was no difference in plasma BNP levels between groups. We compared the percent change in BNP from baseline to assess trend changes in plasma BNP over time between subjects in the two arms of the study. Those in the CON group showed a mean increase in plasma BNP, from baseline, of +24.2% at 12 weeks and +44.3% at 24 weeks. Those in the EX group showed a mean decrease in plasma BNP, from baseline, of -8.1% at 12 weeks and -5.1% at 24 weeks.
Conclusions: Chronic exercise appears to have a positive impact towards maintaining BNP levels over 3-6 months, while non-exercise participants showed a trend towards increasing BNP levels, indicative of an increase in severity of their HF. These preliminary findings suggest exercise has a beneficial effect, centrally, for individuals with HF.