ABSTRACT: Several studies have assessed the effect of the physical activity on plasma homocysteine (Hcy) concentrations, although the findings have been contradictory, and the exact mechanism by which plasma Hcy concentrations varied after an acute intense exercise remains unknown.
Purpose: We studied the effect of different acute aerobic intense exercises on plasma, reduced, and total Hcy (rHcy, tHcy) and cysteine (rCys, tCys) and on its metabolically related vitamins and amino acids. Parallel effects on renal function were assessed by plasma creatinine.
Methods: Fifteen cyclists and 14 kayakers were examined before and 30 ± 5 min after a specific test to exhaustion during a low-intensity training period.
Results: After a bout of specific exercise, the concentrations of aminothiols were increased regardless of the group considered. Plasma concentrations were higher than baseline values in tHcy (17.7 ± 1.5%; P < 0.001), rHcy (10.6 ± 1.6%; P < 0.001), tCys (9.9 ± 1.6%; P < 0.001), and rCys (7.6 ± 2.2%; P < 0.01). Both groups showed significant elevations of pyridoxal-5′-phosphate (PLP; P < 0.01), vitamin B12 (P < 0.001), and creatinine concentrations (P < 0.001) after acute exercises, but no changes were seen in folate. Changes in plasma aminothiols after exercise did not reach significant correlation with changes in free amino acids or baseline vitamins, but significant and positive correlations were observed with changes in plasma PLP, vitamin B12, and creatinine concentrations, when the pooled data were considered.
Conclusions: Our results show that higher plasma concentrations of tHcy after an acute intense exercise are associated to higher concentrations of rHcy, and this effect is independent of the type of exercise, vitamin status, or amino acid metabolic stress but could be related to potential changes in the renal function.