Acute endurance exercise increases fasting plasma homocysteine concentrations in female long-distance runners under similar dietary and living conditions

Background: Increased plasma homocysteine levels are a risk factor for stress fractures and poor bone quality independent of changes in bone mineral density. Homocysteine concentrations vary with dietary habits and exercise. This study investigated changes in plasma homocysteine concentration in female long-distance track and field athletes with a high risk of developing fatigue fractures. Methods: : Six female long-distance track and field athletes with high abilities were assessed under similar dietary conditions, with and without transient endurance exercise. A day before and on the morning of blood sampling, the participants underwent a restricted exercise period (Res), during which exercise was restricted, and an exercise period (Exe), during which transient endurance exercise was performed. Results: : In four participants, the Res plasma homocysteine concentration was significantly lower than that of the Exe ( P <0.05). Furthermore, the mean plasma homocysteine concentration overall in Res was significantly lower than that of Exe ( P <0.01). Conclusions: : Transient endurance exercise increased early morning fasting plasma homocysteine levels the following day when dietary conditions are stable.