The Effect Of An Acute Bout Of Exercise On Serum Vitamin D Metabolite Concentrations

PURPOSE: There is emerging evidence that acute exercise can influence serum vitamin D metabolite concentrations for up to 24 hours. However, previous studies focussed on one or two specific vitamin D metabolites measured using antibody-based methods, and there is a lack of acute exercise studies using gold-standard mass spectrometry measurement. Therefore, we aimed to examine the effect of an acute bout of treadmill exercise on the concentration of serum 25(OH)D3, 25(OH)D2, 3-epi-25(OH)D3, 24,25(OH)D3, 1,25(OH)2D3, D2 and D3 as measured by Liquid Chromatography Mass Spectrometry in healthy adults. METHODS: Thirty-three healthy, non-vitamin D supplementing adults (♀ n = 14, (x̅(SD)) 41(15) yr, Body Mass Index 26.2(3.7) kg/m2) completed two trials (60-minute treadmill exercise at 60% V̇O2 MAX and rest) in a randomised crossover design under overnight fasted conditions. A washout period of >3 days between trials allowed replication of dietary intake and abstinence of moderate-vigorous activity 24 h prior to trials. Venous blood samples were drawn at baseline, immediately (0 h), 1 h and 24 h after the exercise or rest period. Testing occurred between March and November. Post-exercise concentrations were albumin-corrected to account for shifts in blood plasma volume. A mixed effects model was undertaken, with Bonferroni multiple comparison tests. RESULTS: Serum 25(OH)D3 and 1,25(OH)2D3 increased significantly immediately post exercise as compared to resting conditions from baseline (25(OH)D3: +4.28(0.97) nmol/L vs -1.09(0.40) nmol/L, p < 0.0001; 1,25(OH)2D3: +5.33(1.12) pmol/L vs + 0.73(0.18) pmol/L, p = 0.0008). Serum 1,25(OH)2D3 remained significantly elevated compared to resting conditions 1 h following exercise (+3.83(1.33) pmol/L vs + 0.29(1.33) pmol/L, p = 0.013). Serum 3-epi-25(OH)D3, 24,25(OH)D3, 25(OH)D2, D2 and D3 did not change following exercise compared to resting conditions. No significant change was observed for vitamin D metabolites 24 h following exercise. CONCLUSION: An acute bout of moderate intensity exercise transiently increases concentrations of serum 25(OH)D3 and 1,25(OH)2D3 compared to resting conditions. However, effects are short-lived and vitamin D metabolites return to baseline within 24 h of exercise. Supported by BBSRC grant BB/R018928/1.