Influence of training volume and acute physical exercise on the homocysteine levels in endurance-trained men: interactions with plasma folate and vitamin B12

The interrelation between physical exercise and plasma levels of homocysteine (Hcy), vitamin B(12), and folic acid has not been examined. Therefore, we investigated the influence of extensive endurance training and acute intense exercise on plasma concentrations of total Hcy, vitamin B(12), and folic acid in 42 well-trained male triathletes. Examinations and blood sampling took place before and after a 30-day endurance training period as well as before and 1 and 24 h after a competitive exercise (sprint triathlon). Following the training period, no significant change in Hcy levels could be detected for the whole group. Subgroup analysis in quartiles of training volume revealed that - as compared with the lowest quartile (low-training group: 9.1 h training/week) - athletes in the highest training quartile (high-training group: 14.9 h training/week) exhibited a significant decrease in Hcy levels (from 12.7 +/- 2.3 to 11.7 +/- 2.4 micromol/l as compared with levels of 12.5 +/- 1.5 and 12.86 +/- 1.5 micromol/l in the low-training group; p < 0.05). The plasma folate levels were significantly higher in the high-training group at all points of examination (p < 0.05). 1 h and 24 h after competition, the Hcy concentration increased in all athletes independent of the previous training volume (24 h: 12.3 +/- 1.8 vs. 13.5 +/- 2.6 micromol/l; p < 0.001), although the increase was decisively stronger in the low-training group. 1 h after competition, the plasma folate concentration increased (7.03 +/- 2.1 vs. 8.33 +/- 2.1 ng/ml; p < 0.05) in all athletes. Multivariate analysis showed that the exercise-induced increase in the Hcy levels was dependent on baselines levels of folate and training volume, but not on the vitamin B(12) levels. In conclusion, although intense exercise acutely increased the Hcy levels, chronic endurance exercise was not associated with higher Hcy concentrations. Moreover, athletes with the highest training volume, exhibiting also the highest plasma folate levels, showed a decrease in Hcy levels following the training period as well as a much lower increase of the Hcy concentration after acute intense exercise. The combined effect of training and higher plasma folate levels to reduce Hcy should be investigated in future studies.