Vitamin D3 supplementation combined with sprint interval training improves aerobic and anaerobic exercise performance over sprint interval training alone in recreational combat sport athletes

Objectives: Correcting vitamin D deficiency might improve aerobic and anaerobic exercise performance. However, it is unclear if vitamin D ₃ supplementation can convey a positive ergogenic benefit to aerobic and anaerobic exercise performance when combined with sprint interval training (SIT). Methods: Twenty-seven recreational male combat sport athletes were recruited (age: 25 ± 5 years, stature: 178 ± 7 cm, weight: 77 ± 10 kg). Participants completed baseline haematocrit and haemoglobin testing, lower body and upper body VO _2peak testing and two consecutive lower and upper body Wingate tests separated by five minutes rest. Participants were randomly assigned to either the vitamin D ₃ group (VITD) or placebo group (CON) and underwent 6 weeks of twice-weekly SIT and weekly supplementation (50,000 IU.week ⁻¹). Following the intervention, testing was repeated. Results: Haemoglobin (P < 0.001), haematocrit (P < 0.001) and LB VO _2peak (P = 0.016) increased in VITD, remaining unchanged in CON (haemoglobin P = 0.981; haematocrit P = 0.947, LB VO _2peak P = 0.750). UB VO _2peak was unchanged in both groups (P = 0.284). LB and UB time to exhaustion increased in both groups (P < 0.001). LB oxygen kinetics was not affected in either group (P = 0.063) with UB oxygen kinetics improved in VITD (P = 0.028). LB and UB Wingate peak power improved in both groups (P < 0.001). LB Wingate average power improved in both groups (P < 0.001) with VITD increasing average power over CON. Conclusion: Given the results, supplementing 50,000 IU of vitamin D ₃ per week for six weeks combined with six weeks of SIT may improve markers of aerobic and anaerobic performance in recreational male combat sport athletes.