Changes in Vitamin D are Not Associated with Changes in Cardiorespiratory Fitness

Abstract

We investigated the relationship between changes in 25-hydroxyvitamin D (25OHD) and changes in aerobic fitness (VO2max)over 6 months in healthy adults (n = 213, mean ± SD age 44.8 ±16.4 yr, range 20-76 yr, 109 women). 25OHD status was defined as deficient (DEF: 25OHD <50 nmol•L-1, n = 16), insufficient (INS: 25OHD > 50 nmol•L-1 but < 75 nmol•L-1, n = 57), and sufficient (SUF: 25OHD >75 nmol•L-1, n = 140). Tertiles for 25OHD change were computed (lowest: 9.1 nmol•L-1, n = 71). Baseline 25OHD level (β = -0.003; p = 0.83) and change in 25OHD level (β = 0.01; p = 0.50) were not significant predictors of changes in VO2max. Changes in VO2maxwere similar between 25OHD status groups (p = 0.55; DEF = -1.7 ± 2.1, INS = -0.4 ± 3.2; SUF = -0.3 ± 3.1 ml•kg-1•min-1), and 25OHD change tertiles (p = 0.28; lowest = -0.3 ± 2.7, middle = -0.8 ± 3.5, highest = -0.3 ± 2.9 ml•kg-1•min-1). Changes in vitamin D over a 6-month period were not associated with changes in aerobic fitness. Aerobic fitnessis not impacted by temporal variations in 25OHD.