Abstract
RATIONALE: Although cognitive fatigue commonly occurs during sports, effective strategies to improve it during exercise have not been established. OBJECTIVES: This study determined whether high-cocoa flavanol (HCF) consumption improves reaction time and inhibitory executive function impairments during prolonged cognitive load combined with aerobic exercise. METHODS: In this randomized crossover study, 18 healthy males (22 ± 2 years) participated in both low-cocoa flavanol (LCF) and HCF trials. Double-blinded capsules (LCF 50 mg and HCF 500 mg) were consumed 1 h before a 50-min cognitive exercise dual-tasking protocol, which included a color-word Stroop task (CWST) and moderate-intensity cycling. The CWST assessed reaction time and reverse-Stroop interference score as indicators of inhibitory executive process. RESULTS: Reaction time (LCF 774 ± 146 ms vs. HCF 731 ± 101 ms, P < 0.01) and reverse-Stroop interference score (LCF 6.2 [3.2-15.5] vs. HCF 4.6 [1.2-11.4], P < 0.01) were significantly better 1 h after HCF consumption than after LCF consumption, indicating that HCF improved both reaction time and the inhibitory executive process at rest. During the 50-min cognitive-exercise dual-tasking protocol, HCF consumption resulted in faster reaction time (LCF 712 ± 122 ms vs. HCF 685 ± 111 ms, P < 0.05) and better inhibitory executive process (LCF 8.4 ± 5.0 vs. HCF 6.6 ± 3.5, P < 0.05) compared to those following LCF consumption. CONCLUSIONS: These findings suggest that flavanol-rich cocoa may improve reaction time and inhibitory executive process impaired by cognitive fatigue during aerobic exercise.