Effect of an Acute Bout of Endurance Exercise on Serum 25(OH)D Concentrations in Young Adults

Context: Regular exercise or high physical activity levels are associated with higher serum 25-hydroxyvitamin D [25(OH) D] concentrations; however, the effect of acute exercise on serum 25(OH) D concentrations remains unclear. Objective: We aimed to clarify whether acute endurance exercise has a direct effect on the circulating 25(OH) D concentrations in young adults. Design and Setting: Exercise intervention trial in an institutional practice. Patients: Twenty young, active adults (males, n = 10; females, n = 10). Interventions: Participants were asked to perform a cycling exercise for 30 minutes at 70% maximal oxygen uptake. Main Outcome Measures: The serum concentrations of 25(OH) D and other blood parameters were assessed before exercise and at 0, 0.5, 1, 3, and 24 hours after exercise. Results: The serum 25(OH) D concentrations were significantly increased not only at 0 (P < 0.01), 1 (P < 0.05), and 3 hours (P < 0.01) after exercise, but they were also increased at 24 hours (P < 0.05) after acute endurance exercise in young adults. A significant sex 3 time interaction effect was observed (P < 0.05), and the incremental areas under the curve for the 25(OH) D concentrations were significantly higher in men than in the women (P < 0.01). Conclusions: There is a direct effect of endurance exercise on serum 25(OH) D concentrations. In addition, sex disparity was observed in the serum 25(OH) D response to acute endurance exercise, and the increase in 25(OH) D concentrations was greater in men than in women.