Participant characteristics, lung function and multiple-breath nitrogen washout (MBNW) parameters
| Whole group | Repeatability subgroup | |
| Females/males n | 11/16 | 6/9 |
| Age years median (range) | 34 (19–65) | 30 (23–41) |
| BMI kg·m−2 | 24.6±3.4 | 25.1±4.2 |
| Lung function | ||
| FEV1 % predicted# | 105±14 | 101±30 |
| FEV1/FVC % | 83±6 | 84±5 |
| TLCpleth % predicted¶ | 101±23 | 107±11 |
| FRCpleth % predicted¶ | 97±27 | 104±20 |
| MBNW parameters | ||
| Controlled breathing | ||
| FRCCB L | 2.94±0.89 | 2.96±0.88 |
| LCICB | 6.49±0.47 | 6.39±0.36 |
| ScondCB L−1 | 0.019±0.011 | 0.025±0.012 |
| SacinCB L−1 | 0.056±0.020 | 0.061±0.022 |
| VT mL | 1124±37 | 1127±37 |
| VT/FRCMBNW | 0.40±0.16 | 0.42±0.15 |
| RR breaths·min−1 | 10.2±0.89 | 9.86±1.0 |
| Free breathing | ||
| FRCFB L | 2.92±0.86 | 3.00±0.87 |
| LCIFB | 6.70±0.59 | 6.57±0.57 |
| ScondFB L−1 | 0.019±0.012 | 0.018±0.014 |
| SacinFB L−1 | 0.085±0.039 | 0.091±0.041 |
| VT mL | 880±324 | 912±304 |
| VT/FRCMBNW | 0.31±0.12 | 0.32±0.14 |
| RR breaths·min−1 | 12.3±3.53 | 13.6±3.10 |
Data are presented as mean±sd unless otherwise stated. For the repeatability subgroup, results are from the first visit. BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; TLC: total lung capacity; FRC: functional residual capacity; LCI: lung clearance index; Scond: conductive zone ventilation heterogeneity; Sacin: acinar zone ventilation heterogeneity; VT: mean tidal volume across measurements; RR: respiratory rate; pleth: body plethysmography; CB: controlled breathing protocol; FB: free breathing protocol. #: reference equations for predicted values from Quanjer et al. [13]; ¶: reference equations for predicted values from Quanjer et al. [14].