Table 1.

Participant characteristics

	Control	COPD	P value
Participants	13	13	—
Male/female	8/5	10/3	—
Age (years)	64 ± 14	61 ± 14	0.67
Height (cm)	168.7 ± 9.3	170.2 ± 5.5	0.63
Mass (kg)	78.0 ± 15.1	74.4 ± 14.7	0.55
BMI (kg m−2)	27.2 ± 3.7	25.6 ± 3.8	0.26
Smoking history (pack‐years)	3.9 ± 4.5	41.8 ± 29.7	<0.001
Current smoker (n)	0	9	—
Modified MRC dyspnoea (scale 0–4)	0.0 ± 0.0	1.3 ± 0.5	<0.001
Medication use (n)
SABA	0	8	—
ICS	0	8	—
Combined ICS/LABA	0	6	—
β‐blocker	1	2	—
ACE–ARB	0	1	—
Diuretics	1	0	—
Statins	4	3	—
Pulmonary function
FEV1 (L)	3.0 ± 0.8	2.4 ± 0.6	<0.001
FEV1 (% predicted)	106.9 ± 13.9	83.1 ± 18.0	<0.001
FEV1 (Z‐score)	0.13 ± 0.86	−1.41 ± 1.26	<0.001
FEV1/FVC (% predicted)	97.2 ± 5.7	79.9 ± 10.1	<0.001
FEV1/FVC (Z‐score)	−0.75 ± 0.47	−2.28 ± 1.17	<0.001
FRC (% predicted)	98.4 ± 17.6	118.1 ± 20.5	0.015
RV (% predicted)	87.8 ± 18.9	113.9 ± 21.4	0.004
TLC (% predicted)	100.3 ± 15.3	104.5 ± 15.0	0.555
D LCO (% predicted)	93.4 ± 10.5	65.1 ± 21.6	<0.001
Cardiopulmonary peak exercise responses
${\dot{V}}_{{\mathrm{O}}_2}$ (mL kg−1 min−1)	33.3 ± 9.3	24.9 ± 8.9	0.028
${\dot{V}}_{{\mathrm{O}}_2}$ (% predicted)	130 ± 25	88 ± 26	0.002
${\dot{V}}_{\mathrm{C}{\mathrm{O}}_2}$ (L min−1)	2.83 ± 0.86	1.98 ± 0.71	0.011
${\dot{V}}_{\mathrm{E}}$ (L min−1)	92.6 ± 29.3	68.2 ± 17.3	0.017
$P_{\mathrm{ETC}{\mathrm{O}}_2}$ (mmHg)	34.1 ± 4.8	32.8 ± 4.9	0.489
HR (beats min−1)	162 ± 20	144 ± 22	0.065
${S_{\mathrm{pO}}}_{2\mathrm{baseline}}$ (%)	95.8 ± 4.2	97.0 ± 1.5	0.412
${S_{\mathrm{pO}}}_{2\mathrm{peak}}$ (%)	95.6 ± 3.2	95.4 ± 2.5	0.864
Nadir ${\dot{V}}_{\mathrm{E}}$/${\dot{V}}_{\mathrm{C}{\mathrm{O}}_2}$	29.2 ± 2.2	34.9 ± 5.5	<0.001
Change in IC baseline to peak exercise (L)	0.1 ± 0.4	−0.4 ± 0.4	0.007

Data are presented as n or means ± SD. ACE: angiotensin‐converting enzyme; ARB, angiotensin receptor blocker; BMI: body mass index; COPD: chronic obstructive pulmonary disease; D _LCO: diffusing capacity of the lung for carbon monoxide; FEV₁: forced expiratory volume in 1 s; FRC: functional residual capacity; FVC: forced vital capacity; HR: heart rate; IC: inspiratory capacity; ICS: inhaled corticosteroid; LABA: long‐acting β₂‐agonist; MRC: Medical Research Council; $P_{\mathrm{ETC}{\mathrm{O}}_2}$: partial pressure of carbon dioxide; RV: residual volume; SABA: short‐acting β‐agonist; S _{pO 2}: oxygen saturation measured by pulse oximeter; TLC: total lung capacity; ${\dot{V}}_{\mathrm{C}{\mathrm{O}}_2}$: carbon dioxide production; ${\dot{V}}_{\mathrm{E}}$: minute ventilation; ${\dot{V}}_{{\mathrm{O}}_2}$: oxygen uptake. Z‐score calculated using Global Lung Initiative 2012 Equations (Quanjer et al. 2012).