Table 1.

Subject characteristics, pulmonary function and maximal exercise data

	Men	Women
Age (years)	29 ± 3	28 ± 2
Mass (kg)	74 ± 2	60 ± 2*
Height (cm)	179 ± 2	166 ± 3*
FVC (l)	5.4 ± 0.2	4.0 ± 0.2*
FVC (% predicted)	98 ± 4	101 ± 5
FEV1 (l)	4.4 ± 0.2	3.2 ± 0.1*
FEV1 (% predicted)	98 ± 3	96 ± 3
FEV1/FVC (%)	82 ± 3	81 ± 3
Work rate (W)	338 ± 17	235 ± 7*
Test time (min)	22 ± 2	16 ± 1*
HR (beats min−1)	186 ± 3	185 ± 4
${\dot{V}}_{{\mathrm{O}}_2}$ (l min−1)	4.5 ± 0.2	3.1 ± 0.1*
${\dot{V}}_{{\mathrm{O}}_2}$ (ml kg−1 min−1)	60.5 ± 1.6	52.7 ± 2.7*
${\dot{V}}_{{\mathrm{O}}_2}$ (% predicted)	135 ± 5	145 ± 8
${\dot{V}}_{\mathrm{C}{\mathrm{O}}_2}$ (l min−1)	4.7 ± 0.1	3.3 ± 0.1*
RER	1.09 ± 0.02	1.05 ± 0.02
V T (l)	3.2 ± 0.2	2.1 ± 0.1*
f b (beats min−1)	57 ± 3	59 ± 4
V T/FVC (%)	59 ± 1	53 ± 3
V T/T I (l sec−1)	6.2 ± 0.2	4.1 ± 0.2*
V T/T E (l sec−1)	5.9 ± 0.2	3.9 ± 0.2*
T I/T tot (%)	49 ± 1	49 ± 1
${\dot{V}}_{\mathrm{E}}$ (l min−1)	180 ± 6	120 ± 5*
${\dot{V}}_{\mathrm{E}}$/${\dot{V}}_{{\mathrm{O}}_2}$	40 ± 1	39 ± 1
${\dot{V}}_{\mathrm{E}}$/${\dot{V}}_{\mathrm{C}{\mathrm{O}}_2}$	38 ± 1	37 ± 1
ERV (% FVC)	34 ± 2	38 ± 2
∆P oe (cmH2O)	56 ± 4	47 ± 4
WOB (J min−1)	625 ± 42	366 ± 42*
WOB/${\dot{V}}_{\mathrm{E}}$ (J l−1)	3.5 ± 0.2	3.0 ± 0.2
PTPI (cmH2O l−1 s−1)	595 ± 35	552 ± 50
${\dot{V}}_{\mathrm{Ecap}}$ (l min−1)	212 ± 7	160 ± 9*
${\dot{V}}_{\mathrm{E}}$/${\dot{V}}_{\mathrm{Ecap}}$ (%)	85 ± 1	76 ± 5
EFL (n)	6/8	5/8
EFL (%)	26 ± 1	21 ± 5

Values are means ± SEM. EFL, expiratory flow limitation defined as percentage overlap of tidal breaths on the maximal expiratory flow volume curve; ERV, expiratory reserve volume; f _b, breathing frequency; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; HR, heart rate; ∆P _oe, oesophageal pressure swing; PTP_I, inspiratory pressure–time product; RER, respiratory exchange ratio; T _E, expiratory time; T _I, inspiratory time; ${\dot{V}}_{\mathrm{C}{\mathrm{O}}_2}$, carbon dioxide output; ${\dot{V}}_{\mathrm{Ecap}}$, ventilatory capacity; ${\dot{V}}_{{\mathrm{O}}_2}$, oxygen uptake; V _T, tidal volume; WOB, work of breathing. ^*Significantly different from men, P < 0.05.