Figure 4

VE/VCO ₂ by confidence intervals in relation to different time points and linear regression for time points 1 and 5 with respect to FEV₁%. (A) Confidence interval of VE/VCO₂ for the cystic fibrosis group (CFG) (n=64) and control group (CG) (n=64). Data are presented as the confidence interval of the median. Time points analyzed: (1) baseline (rest), (2) 1–2 min of activity, (3) 3–4 min of activity, (4) 5–6 min of activity, and (5) immediately postexercise. α=0.01 by Bonferroni correction. The Mann–Whitney test was used to compare the CFG and CG, and correlations between the time points in each group were determined using the Friedman test (non-parametric, repeated measures); in cases with a positive p-value, the Wilcoxon signed-rank test was performed. Higher values were observed in the CG at all time points (p≤0.001). In the cluster analysis for the CFG, time point 1 differed from 2 to 5; time point 2 differed from 1 and 4; time point 3 differed from 1 and 5; time point 4 differed from 1, 2, and 5; and time point 5 differed from 1, 3, and 4 (p≤0.001). For the CG, time point 1 differed from 2 to 5; time point 2 differed from 1, 3, and 4; time point 3 differed from 1, 2, and 4; time point 4 differed from 1, 2, 3, and 5; and time point 5 differed from 1 and 4 (p≤0.001). (B) Linear regression of the VE/VCO₂ and FEV₁%. Time point 1 - [(Combined: y= 52.5615 – 0.1343x) (p≤0.0001); R²=0.01522; (CFG: y= 51.8380 – 0.1139x) (p=0.0056); R²=0.1122; (CG: y = 48.0635 – 0.0935x) (p=0.1756); R²=0.02986]. (C) Linear regression of the EV/VCO₂ and FEV₁%. Moment 5 - [(Combined: y= 47.2563 – 0.1411x) (p≤0.001); R²=0.1622; (CFG: y= 46.6691 – 0.1139x) (p=0.024); R²=0.08373; (CG: y= 35.5437 – 0.02961x) (p=0.5310); R²=0.006467].