Pre-exercise intake of different carbohydrates modifies ischemic reactive hyperemia after a session of anaerobic, but not after aerobic exercise

The acute ingestion of a supplement with different glycemic carbohydrates, including fructose, is a typical practice for athletes before exercising. Observational evidence suggests that different metabolic responses may modify the exercise-stimulated endothelium-dependent vasodilation. The purpose of the present study was to investigate whether endothelial reactivity, stimulated by anaerobic exercise (AnE) or aerobic exercise (AE), both performed with glycemic supplementation, is modified by the addition of fructose. Twenty physically trained men ingested an oral dose of glucose (G) or glucose plus fructose (F) 15 minutes before starting a 30-minute session of AnE (10 sets of 10 repetitions of half squat) or AE (cycling). The combination resulted in 4 randomized interventions in a crossover design in which all subjects performed all experimental conditions: G + AnE, F + AnE, G + AE, and F + AE. Ischemic reactive hyperemia (IRH), glycemia, plasma lipoperoxides (LPOs), nitric oxide (NO), and lactate were determined at baseline, exercise, and acute recovery time points. Immediately after AnE, IRH was 26.35% higher in F + AnE than in G + AnE (p < 0.05); this difference rose to 27.24% at the end of the recovery period (p < 0.05). The glycemic peak in F + AnE was lower than in G + AnE (p < 0.05), and there was a second peak during recovery (p < 0.05). There were no differences observed in LPO between anaerobic trials, but the NO bioavailability increased and was higher in F + AnE than in G + AnE after exercise and recovery (p < 0.05). Residual lactate was also higher under the F + AnE condition (p < 0.05). During AE, there were no differences in IRH, glycemia, or NO between groups, but LPO was significantly higher after F supplementation. These results suggest that the addition of fructose to a single G supplement ingested before a glycolitic exercise can modify the glucoregulation and increases ischemic reactive hyperemia.