Table 2 Incremental exercise variables in COPD patients classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria

At peak exercise

Dyspnea, Borg scale

5.6 (1.8) [5.0 (4.0; 7.0)]

6.0 (1.9) [6.0 (5.0; 8.0)]

0.2126

\(\rm{\dot V}\)_O2, mL⋅min⁻¹ ⋅ kg⁻¹

14.9 (3.8) [15.2 (11.7; 17.3)]

10.6 (2.3)

< 0.0001

R

1.10 (0.10)

1.01 (0.08) [1.01 (0.96; 1.05)]

< 0.0001

\(\rm{\dot V}\)_E, L ⋅ min⁻¹

43.7 (12.6)

28.0 (6.6)

< 0.0001

V_T, mL

1397 (320)

987 (239)

< 0.0001

f_R, breaths ⋅ min^− 1

31.7 (6.1)

28.9 (5.3)

0.0079

T_I/Ttot

0.41 (0.05) [0.41 (0.38; 0.43)]

0.34 (0.05)

< 0.0001

\(\rm{\dot V}\)_E/\(\rm{\dot V}\)_O2

49.7 (10.1)

48.0 (7.4) [47.0 (44.0; 51.2)]

0.2892

\(\rm{\dot V}\)_E/\(\rm{\dot V}\)_CO2

45.1 (8.7)

47.8 (8.4) [46.8 (42.7; 51.0)]

0.1623

1−\(\rm{\dot V}\)_E/MVV, %

29.2 (15.4)

8.4 (19.0) [11.9 (2.9; 19.4)]

< 0.0001

HR, beats ⋅ min^− 1

124 (17.6)

112 (16.8)

0.0005

HR/predicted maximum HR, %

80.8 (12.4)

80.0 (10.7)

0.7007

SpO₂, %

93 (4) [95 (91; 97)]

91 (5) [92 (87; 94)]

0.0004

O₂ pulse, mL ⋅ beats^− 1

7.3 (1.9)

5.4 (1.6) [5.1 (4.2; 6.4)]

< 0.0001

OUES

1319 (420)

1135 (440) [1115 (880; 1328)]

0.0161

ΔF_O2, %

2.58 (0.50) [2.52 (2.28; 2.74)]

2.59 (0.38)

0.5014

During exercise

ΔF_O2 max., %

2.88 (0.57) [2.78 (2.47; 3.11)]

2.72 (0.41)

0.2062

\(\rm{\dot V}\)_E-\(\rm{\dot V}\)_CO2 slope

39.1 (8.9)

40.3 (10.9) [39.2 (34.2; 43.2)]

0.8073

\(\rm{\dot V}\)_E/\(\rm{\dot V}\)_CO2 nadir

43.1 (7.9)

46.8 (7.6) [46.0 (41.0; 50.0)]

0.0294

Number of patients reaching AT, n (%)

49 (96)

51 (72)

0.0006

\(\rm{\dot V}\)_O2 at AT, mL ⋅ min⁻¹

601 (178) [575 (490; 670)]

481(104)

0.0001

Number of patients reaching RCP, n (%)

19 (37)

7 (10)

0.0003