The Effect of Vitamin D Supplementation on Physical Capacity among Active College-Aged Males.

Vitamin D supplementation can affect strength and power; however, the effect on both aerobic and anaerobic performance remains unclear. Here, we investigate the effects of eight weeks of a high dose of vitamin D supplementation and its impact on circulating 25-hydroxyvitamin D (25-OH-D) concentrations and selected indicators of physical capacity. Subjects ( = 28, age 21.1 ± 1.6) were divided into two groups: supplemented (SUP), which was given 6000 IU of vitamin D daily for eight weeks; and placebo group (PLA). Serum 25-OH-D concentrations were determined in pre- and post-intervention. Aerobic (VO test) and anaerobic (Wingate Anaerobic Test) capacity were determined before and after the supplementation. The mean baseline concentration of 25-OH-D was recognized as deficient (20 ng/mL) and significantly increased over time in the supplemented group ( < 0.01, η = 0.86), whilst it remained unchanged in the placebo group. Moreover, the supplementation caused a significant improvement in maximal aerobic ( < 0.05, η = 0.27) and anaerobic power ( < 0.01, η = 0.51) whereas no changes were observed in PLA group. The VO differences were also significant in the supplemented group ( < 0.05). In summary, the changes in aerobic and anaerobic capacity observed in this study were associated with a serum concentration of 25-OH-D. Our data imply that vitamin D supplementation with a dose of 6000 IU daily for eight weeks is sufficient to improve physical capacity and vitamin D status.