Table 4.
Cardiopulmonary exercise testing (CPET) parameters (mean ± SD)
| Variable | H | CS | CR | COM | F Score | P value | Post hoc comparison |
|---|---|---|---|---|---|---|---|
| CPET | |||||||
| V̇O2 at Rest (ml/kg/min) | 4.8 ± 0.9 | 4.9 ± 1.0 | 5.5 ± 1.2 | 5.5 ± 1.8 | 2.583 | 0.057 | |
| V̇O2 at VT1 (ml/kg/min) | 12.3 ± 1.9 | 14.5 ± 3.9 | 17.2 ± 3.0 | 18.2 ± 5.6 | 14.665 | < 0.001 | †***, §***, ¥** |
| V̇O2 at Peak (ml/kg/min) | 30.5 ± 5.4 | 34.4 ± 7.2 | 44.3 ± 7.4 | 43.9 ± 13.1 | 17.788 | < 0.001 | †***, §***, #**, ¥*** |
| V̇O2 at VT1 (% of predicted peak) | 43 ± 7 | 46 ± 11 | 49 ± 11 | 56 ± 17 | 6.470 | < 0.001 | §***, ¥*** |
| V̇O2 at Peak (% of predicted) | 108 ± 16 | 111 ± 19 | 122 ± 19 | 133 ± 25 | 9.510 | < 0.001 | §***, ¥*** |
| Workload at VT1 (W) | 70 ± 15 | 85 ± 33 | 100 ± 26 | 109 ± 34 | 11.036 | < 0.001 | †**, §***, ¥** |
| Workload at peak (W) | 231 ± 35 | 255 ± 61 | 308 ± 60 | 304 ± 65 | 12.641 | < 0.001 | †***, §***, #**, ¥** |
| Workload at peak (% of predicted) | 97 ± 17 | 100 ± 23 | 115 ± 16 | 127 ± 32 | 10.692 | < 0.001 | †*, §***, ¥*** |
| W/Kg at VT1 | 0.74 ± 0.17 | 0.92 ± 0.36 | 1.20 ± 0.29 | 1.38 ± 0.38 | 25.266 | < 0.001 | †***, §***, #*, ¥** |
| W/Kg at Peak | 2.44 ± 0.47 | 2.77 ± 0.68 | 3.73 ± 0.67 | 3.89 ± 0.82 | 14.086 | < 0.001 | †***, §***, #***, ¥*** |
| Δ V̇O2 (l/min)/Δ Work (W) | 10.9 ± 1.0 | 11.2 ± 2.2 | 11.2 ± 0.9 | 11.5 ± 0.7 | 1.971 | 0.123 | |
| Lactate at rest (mmol/L) | 1.3 ± 0.5 | 1.3 ± 0.5 | 1.4 ± 0.4 | 1.2 ± 0.4 | 0.691 | 0.559 | |
| Lactate at peak (mmol/L) | 12.1 ± 2.5 | 13.1 ± 2.3 | 14.1 ± 2.4 | 14.2 ± 1.5 | 5.393 | 0.002 | †*, §** |
| O2 Pulse | 16.7 ± 3.8 | 18.5 ± 4.7 | 21.1 ± 3.7 | 21.1 ± 4.7 | 7.131 | < 0.001 | †** §** |
| O2 Pulse (% of predicted peak) | 97 ± 20 | 105 ± 20 | 119 ± 17 | 126 ± 22 | 12.045 | < 0.001 | †*, §***, ¥* |
| Heart rate profile | |||||||
| HR at rest (bpm) | 82 ± 11 | 84 ± 13 | 77 ± 15 | 73 ± 8 | 4.791 | 0.004 | §*, ¥** |
| HR at VT1 (bpm) | 106 ± 14 | 108 ± 15 | 107 ± 12 | 107 ± 8 | 0.163 | 0.921 | |
| HR at peak (bpm) | 172 ± 15 | 175 ± 16 | 178 ± 7 | 175 ± 8 | 0.833 | 0.479 | |
| % of predicted max HR | 110 ± 10 | 108 ± 9 | 107 ± 5 | 108 ± 7 | 0.650 | 0.585 | |
| HRR after 1-min (bpm) | 25 ± 10 | 28 ± 11 | 30 ± 16 | 26 ± 8 | 1.053 | 0.372 | |
| Blood pressure (mmHg) | |||||||
| Resting systolic BP (mmHg) | 126 ± 10 | 120 ± 11 | 117 ± 10 | 121 ± 10 | 3.670 | 0.015 | †* |
| Resting diastolic BP (mmHg) | 85 ± 7 | 84 ± 8 | 79 ± 8 | 79 ± 6 | 5.795 | 0.001 | †*, §**, ¥* |
| VT1 systolic BP (mmHg) | 142 ± 17 | 144 ± 15 | 135 ± 17 | 142 ± 14 | 1.381 | 0.252 | |
| VT1 diastolic BP (mmHg) | 85 ± 17 | 83 ± 16 | 76 ± 9 | 82 ± 12 | 1.681 | 0.175 | |
| Peak systolic BP (mmHg) | 169 ± 20 | 171 ± 18 | 160 ± 23 | 166 ± 37 | 1.392 | 0.249 | |
| Peak diastolic BP (mmHg) | 73 ± 27 | 79 ± 19 | 66 ± 20 | 73 ± 22 | 1.526 | 0.212 | |
| Ventilation | |||||||
| BF at rest (breaths/min) | 17 ± 5 | 16 ± 5 | 14 ± 3 | 16 ± 4 | 0.998 | 0.397 | |
| BF at VT1 (breaths/min) | 20 ± 7 | 21 ± 6 | 18 ± 4 | 20 ± 4 | 1.158 | 0.329 | |
| BF at peak (breaths/min) | 47 ± 12 | 47 ± 12 | 46 ± 6 | 51 ± 11 | 1.445 | 0.234 | |
| V̇E/ V̇CO2 at rest | 30.8 ± 4.8 | 30.5 ± 5.3 | 28.1 ± 2.0 | 28.0 ± 3.1 | 3.462 | 0.019 | |
| V̇E/ V̇CO2 at VT1 | 27.8 ± 4.0 | 26.7 ± 4.0 | 24.1 ± 1.7 | 24.3 ± 2.0 | 7.807 | < 0.001 | †**, §**, ¥* |
| V̇E/ V̇CO2 at peak | 34.4 ± 5.5 | 33.2 ± 4.0 | 30.5 ± 3.1 | 31.3 ± 3.3 | 4.431 | 0.006 | †*, §* |
| V̇E/ V̇CO2 slope | 29.6 ± 5.1 | 27.9 ± 5.3 | 24.1 ± 6.0 | 25.5 ± 2.6 | 6.422 | < 0.001 | †**, §* |
| pCO2 rest | 5.2 ± 0.8 | 4.9 ± 0.6 | 5.1 ± 0.6 | 5.1 ± 0.5 | 1.927 | 0.130 | |
| pCO2 peak | 4.5 ± 0.9 | 4.3 ± 0.8 | 4.6 ± 0.6 | 4.4 ± 0.6 | 0.855 | 0.467 | |
| OUES | 3.01 ± 0.58 | 3.34 ± 0.96 | 4.88 ± 1.11 | 3.79 ± 0.93 | 3.689 | 0.014 | †** |
| Resting spirometry | |||||||
| FEV1 value (L) | 3.7 ± 0.6 | 3.9 ± 0.8 | 4.3 ± 0.4 | 4.1 ± 0.6 | 2.859 | 0.041 | |
| FEV1% predicted | 96 ± 14 | 93 ± 11 | 97 ± 14 | 102 ± 13 | 2.362 | 0.076 | |
| FVC value (L) | 4.7 ± 0.9 | 5.2 ± 1.1 | 5.7 ± 0.6 | 5.3 ± 0.7 | 4.751 | 0.004 | †** |
| FVC % predicted | 99 ± 14 | 101 ± 13 | 106 ± 11 | 108 ± 10 | 3.142 | 0.028 | §* |
Bold denotes a statistically significant result, with the level denoted by asterisk(s)
Abbreviations: VT1, 1st ventilatory threshold; HR, heart rate; HRR, heart rate recovery; BP, blood pressure; BF, breathing frequency; OUES, oxygen uptake efficiency slope. H, hospitalised illness; CS, community illness with on-going symptoms (community-symptomatic), CR, community illness now recovered (community-recovered; COM, age-, gender- and job-role-matched comparison population. There was no significant difference between H versus CS and CR versus COM for any CPET-related parameter
†, H vs. CR; §, H vs. COM; #, CS vs. CR; ¥, CS vs. COM. Level of significance: *P < 0.05, **P < 0.01 ***P < 0.001