Figure 4From: Vitamin D supplementation during rehabilitation in COPD: a secondary analysis of a randomized trialChanges in exercise performance (6MWD = Six Minutes Walking Distance; VO 2max = Maximal Oxygen Uptake; W max = Maximal Workload) in the vitamin D group (■) and in the placebo group (□). Data are expressed as mean±SD. Baseline results are compared with results after 3 months of rehabilitation. Results with p <0.05 are indicated with (*).Back to article page