β-alanine and L-histidine supplementation associated with combined training increased functional capacity and maximum strength in heart failure rats.

Combined training (CT) has been associated with positive responses in the clinical status of patients with chronic heart failure (CHF). Other non-pharmacological tools, such as amino acid supplementation, may further enhance its adaptation. However, the effects of β-alanine and L-histidine supplementation in CHF remain unclear. In the present study, the aim was to test whether supplementing carnosine precursors with CT could present improved responses in the functional capacity and echocardiographic variables of rats with CHF. Twenty-four Wistar rats, were submitted to myocardial infarction and allocated to three groups: sedentary (SED, n = 8), CT supplemented with placebo (CT-P, n = 8), and CT with CHF supplemented with β-alanine and L-histidine (CT-S, n = 8). The trained animals were submitted to a strength protocol 3 times per week with intensity of 65-75% of one repetition maximum test. Aerobic training was conducted two times per week (50 minutes, 15 m per minute). The supplemented group received β-alanine and L-histidine orally (each 250 mg/kg per day). No changes in echocardiographic and morphological parameters were found among the groups (P > 0.05). Functional capacity, delta V̇O_2max , and maximum strength were higher in CT-P than in SED and even higher in CT-S than in CT-P (P < 0.01). The CT was able to improve functional capacity, but the supplementation was shown to enhance these parameters even further in the CHF rats. We concluded that the increase in functional capacity and strength gained through CT and supplementation were associated with the improvement in peripheral parameters with no changes in cardiac variables. NEW FINDINGS: What is the central question of the study? The study was designed to evaluate whether β-alanine with L-histidine supplementation associated with endurance and strength training could improve echocardiographic parameters, functional capacity, and maximum strength in rats with chronic heart failure. What is the main finding and its importance? β-alanine with L-histidine supplementation associated with endurance and strength training increased functional capacity and maximum strength through increasing exercise capacity peripherally but did not affect echocardiographic parameters in rats with chronic heart failure. This article is protected by copyright. All rights reserved.