Effects of a single dose of a betalain-rich concentrate on determinants of running performance and recovery muscle blood flow: a randomized, triple-blind, placebo-controlled, crossover trial

Abstract

Purpose: This study aimed to examine the effects of a single dose of a betalain-rich concentrate (BRC) on determinants of running performance and recovery lactate clearance. Methods: In this a randomized, triple-blind, placebo-controlled, crossover trial, 17 male recreational runners (Age: 19.0 ± 1.0 years; Height: 176.8 ± 6.2 cm; Weight: 70.62 ± 8.1 kg; Body fat: 12.8 ± 0.03%; VO2max: 58.9 ± 8.6 ml/kg/min) consumed an acute dose of a BRC (100 mg) or a placebo (100 mg of dextrose; CON) and performed a running economy protocol (RE) at velocities corresponding to 60% and 80% of maximal oxygen consumption (VO2max) followed by a VO2max test. Both exercise and recovery skeletal muscle oxygenation (SmO2) were assessed via near-infrared spectroscopy (NIRS), and recovery lactate was obtained. Results: BRC resulted in lower heart rate (HR) at velocities corresponding to 80% of VO2max (p = 0.05) and maximum HR (HRmax; p = 0.01), and a lower rating of perceived exertion (RPE) at velocities corresponding to 60% of VO2max (p = 0.02) when compared to CON. BRC also improved post-exercise SmO2 at 3 (p = 0.05), 4 (p = 0.02), and 5 min (p = 0.01) but not lactate clearance (p > 0.05). BRC did not significantly improve RE or VO2max (p > 0.05). Conclusions: A single dose of BRC did not enhance RE or VO2max. However, the observed improvements in exercise HR, RPE, and SmO₂ suggest that BRC may confer cardiovascular benefits for exercise and recovery.