Table 4 Cardiopulmonary exercise testing data in the control and long COVID groups

HR at peak (beats/min)

170 ± 17

158 ± 18

0.0619

          (% predicted)

97 ± 6

92 ± 9

0.1326

VO₂ at peak (L/min)

1.78 ± 0.57

1.40 ± 0.34

0.0378

          (mL/kg/min)

26.7 ± 7.4

18.6 ± 4.7

0.0015

          (% predicted)

91 ± 18

76 ± 18

0.0340

HR/%VO₂ slope

1.00 ± 0.15

0.77 ± 0.26

0.0114

RER at peak

1.28 ± 0.11

1.27 ± 0.09

0.7483

RPE at peak (median, IQR)

17 (16-18)

19 (18-19)

0.0081*

Dyspnoea at peak (median, IQR)

5 (4-8)

8 (5-9)

0.0515*

SpO₂ (%) at peak

99 ± 1

99 ± 1

0.8966

VCO₂ at peak (L/min)

2.29 ± 0.83

1.76 ± 0.52

0.0477

P_ETCO₂ at peak

39.6 ± 4.7

33.6 ± 3.8

0.0007

O₂ pulse peak (mL/beat)

10.6 ± 2.8

8.9 ± 2.0

0.0650

Peak SBP (mmHg)

177 ± 21

171 ± 26

0.5115

Peak DBP (mmHg)

88 ± 12

90 ± 15

0.6286

V_E at peak (L/min)

71.5 ± 29.2

66.4 ± 22.4

0.6012

Breathing reserve

43 ± 18

42 ± 24

0.8708

f_B at peak (breaths/min)

36 ± 10

37 ± 9

0.8705

V_T at peak (L)

1.98 ± 0.47

1.83 ± 0.40

0.3440

V_E/VCO₂ ratio at peak

31.4 ± 4.9

38.7 ± 5.4

0.0005

V_E/VO₂ ratio at peak

39.8 ± 7.6

48.4 ± 8.6

0.0095

V_E/VCO₂ slope

27.7 ± 4.8

37.8 ± 4.4

0.0003

Nadir V_E/VCO₂

25.0 ± 2.4

30.1 ± 5.0

0.0020

VO₂ at AT (mL/kg/min)

18.7 ± 5.6

12.6 ± 4.3

0.0025

          (% of VO₂ peak)

68 ± 10

66 ± 13

0.6490

P_ETCO₂ at AT (mmHg)

44 ± 4

38 ± 6

0.0041

V_E/VCO₂ at AT

25.5 ± 2.4

30.4 ± 5.4

0.0042

HR at AT (beats/min

132 ± 13

121 ± 15

0.0453

          (% of peak HR)

76 ± 5

77 ± 8

0.6181

Δ from rest (beats/min)

61 ± 18

38 ± 16

0.0009

VO₂/WR slope

8.2 ± 1.2

8.2 ± 1.5

0.9283

Heart rate recovery 1 min (beats/min)

19 ± 7

17 ± 5

0.4635