Table 3 Square of the correlation coefficient of parameters related to OUES in COPD patients (n = 122)

Peak incremental exercise parameters

Dyspnoea, Borg scale

0.02

0.00

0.03

\(\rm{\dot V}\)_O2, mL ⋅ min⁻¹ ⋅ kg

0.35

0.60

0.19

\(\rm{\dot V}\)_E, L ⋅ min⁻¹

0.27

0.25

0.26

V_T, mL

0.27

0.30

0.19

f_R, breaths ⋅ min^− 1

0.01

0.01

0.00

T_I/Ttot

0.03

0.01

0.00

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

0.26

0.31

0.14

HR, beats ⋅ min^− 1

0.05

0.09

0.01

O₂ pulse, mL ⋅ beats^− 1

0.47

0.66

0.35

ΔF_O2, %

0.21

0.33

0.17

During exercise

ΔF_O2 max., %

0.18

0.34

0.07

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

0.25

0.29

0.20

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

0.22

0.28

0.08

AT (\(\rm{\dot V}\)_O2), mL ⋅ min⁻¹

0.39

0.46

0.33

Pulmonary function and others

FEV₁, L

0.16

0.19

0.12

VC, L

0.19

0.08

0.07

FVC, L

0.18

0.07

0.14

IC, L

0.17

0.16

0.10

Age, y

0.00

0.00

0.02

BMI, kg ⋅ m^− 2

0.14

0.13

0.15