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Table 1 Demographic data and results

From: Decreased oxygen extraction during cardiopulmonary exercise test in patients with chronic fatigue syndrome

Female
  CFS CFI Healthy ANOVA
  n=178 n=172 n=11 P
Age (years) 37.3 ± 12.1 37.9 ± 12.3 42.2 ± 14.8 0.421
Weight (kg) 69.5 ± 15.0 67.5 ± 13.1 68.6 ± 13.2 0.412
BSA (m2) 1.81 ± 0.20 1.78 ± 0.18 1.79 ± 0.17 0.497
Haemoglobin (mmol/l) 8.45 ± 0.55 8.46 ± 0.51   0.846
Rest      
HR (beats/min) 96.1 ± 14.9 93.5 ± 16.8 87.7 ± 11.1 0.113
V’O2 (ml/min/kg) 5.46 ± 0.99 5.41 ± 0.93 5.18 ± 0.98 0.635
O2 pulse (ml/beat) 4.00 ± 0.85 3.95 ±0.82 4.09 ± 0.90 0.784
RER   0.86 ± 0.07 0.86 ± 0.07 0.81 ± 0.03 0.073
V’E/V’CO2   34.2 ± 4.3 34.3 ± 4.1 34.7 ± 3.0 0.924
SVI (ml/m2) 42.8 ±7.0 42.3 ±7.6 43.4 ± 10.4 0.797
Cardiac index (L/min/m2) 4.10 ± .081 3.97 ± 0.92 3.80 ± 0.95 0.294
O2 extraction (ml/100ml) 6.48 ± 1.65 6.58 ± 1.72 6.96 ± 1.63 0.620
Anaerobic threshold      
HR (beats/min) 112.0 ± 15.6 112.3 ± 15.2 113.3 ± 8.7 0.955
V’O2 (ml/min/kg) 10.9 ± 2.6 11.6 ± 2.7 13.7 ± 3.6 0.001
O2 pulse (ml/beat) 6.75 ± 1.63 6.95 ± 1.67 8.33 ± 2.31 0.009
RER   0.84 ± 0.07 0.85 ± 0.08 0.81 ± 0.06 0.216
V’E/V’CO2   29.7 ± 3.5 28.8 ± 3.5 27.6 ± 1.7 0.025
SVI (ml/m2) 45.7 ± 7.9 45.0 ± 8.2 48.2 ± 11.8 0.382
Cardiac index (L/min/m2) 5.12 ± 1.10 5.11 ± 1.21 5.52 ± 1.64 0.534
O2 extraction (ml/100ml) 8.30 ± 2.08 8.77 ± 2.23 9.86 ± 2.37 0.019
Peak exercise      
HR (beats/min) 158.4 ± 19.3 159.6 ± 18.6 164.1 ± 11.3 0.250
V’O2 (ml/min/kg) 20.3 ± 5.0 22.2 ± 5.3 27.4 ± 7.2 0.000
V’O2/pred. % 80.6 ± 17.9 83.1 ± 18.0 105.4 ± 18.8 0.000
O2 pulse (ml/beat) 8.89 ± 2.17 9.26 ± 2.08 11.36 ± 2.89 0.001
RER   1.16 ± 0.10 1.18 ± 0.10 1.20 ± 0.11 0.094
V’E/V’CO2   30.2 ± 3.7 29.7 ± 3.7 27.9 ± 2.4 0.103
SVI (ml/m2) 45.9 ±7.9 45.4 ± 8.3 47.6 ± 11.2 0.797
Cardiac index (L/min/m2) 7.33 ± 1.77 7.39 ± 1.78 7.87 ± 1.96 0.618
O2 extraction (ml/100ml) 10.83 ± 2.80 11.62 ± 2.90 13.45 ± 2.72 0.001
Slope      
ΔQ’/ΔV’O2 (L/L) 7.35 ± 2.40 6.80 ± 1.99 5.85 ± 1.23 0.012
Male      
   CFS CFI Healthy ANOVA
   n=25 n=51 n=7 P
Age (years) 41.6 ± 12.3 41.8 ± 9.9 49.4 ± 13.8 0.215
Weight (kg) 88.9 ± 15.7 80.0 ± 12.8 94.3 ± 13.9 0.005
BSA (m2) 2.12 ± 0.21 2.02 ± 0.17 2.19 ± 0.16 0.016
Haemoglobin (mmol/l) 9.34 ± 0.66 9.53 ± 0.56   0.263
Rest      
HR (beats/min) 89.5 ± 15.8 88.4 ± 15.1 79.4 ± 16.2 0.303
V’O2 (ml/min/kg) 5.08 ± 0.81 5.51 ± 0.90 4.57 ± 0.79 0.093
O2 pulse (ml/beat) 5.24 ± 1.20 5.01 ± 0.94 5.56 ± 1.47 0.025
RER   0.84 ± 0.07 0.88 ± 0.08 0.87 ± 0.04 0.226
V’E/V’CO2   33.6 ± 4.4 34.4 ± 5.7 36.5 ± 3.0 0.436
SVI (ml/m2) 43.4 ± 8.0 45.9 ± 6.9 41.2 ± 6.7 0.182
Cardiac index (L/min/m2) 3.86 ± 0.83 4.05 ±0.96 3.31 ± 1.02 0.152
O2 extraction (ml/100ml) 6.96 ± 1.76 6.70 ± 1.68 8.20 ± 2.82 0.124
Anaerobic threshold      
HR (beats/min) 103.6 ± 14.6 107.0 ± 14.3 102.1 ± 19.2 0.529
V’O2 (ml/min/kg) 11.8 ± 2.8 13.4 ± 3.3 13.7 ± 3.1 0.093
O2 pulse (ml/beat) 9.97 ± 2.50 9.92 ± 2.49 12.8 ± 3.5 0.025
RER   0.84 ± 0.09 0.87 ± 0.06 0.86 ± 0.08 0.250
V’E/V’CO2   28.0 ± 3.6 26.2 ± 3.0 27.3 ± 3.1 0.089
SVI (ml/m2) 47.5 ± 8.9 51.3 ± 7.0 45.7 ± 6.4 0.049
Cardiac index (L/min/m2) 4.95 ± 1.09 5.48 ± 1.07 4.77 ± 1.44 0.082
O2 extraction (ml/100ml) 9.86 ± 2.02 9.74 ± 3.09 13.0 ± 4.32 0.025
Peak exercise      
HR (beats/min) 154.6 ± 19.4 160.5 ± 20.6 151.4 ± 16.2 0.328
V’O2 (ml/min/kg) 24.0 ± 7.2 28.9 ± 7.1 27.3 ± 3.7 0.019
V’O2/pred. % 73.9 ± 17.5 83.4 ± 19.2 96.2 ± 11.4 0.011
O2 pulse (ml/beat) 13.5 ± 3.0 14.2 ± 3.0 17.1 ± 3.0 0.023
RER   1.19 ±0.11 1.24 ± 0.12 1.29 ± 0.06 0.100
V’E/V’CO2   28.9 ± 5.2 27.9 ± 3.8 29.2 ± 4.0 0.537
SVI (ml/m2) 47.4 ± 10.5 50.4 ± 9.4 44.4 ± 8.6 0.182
Cardiac index (L/min/m2) 7.44 ±2.13 8.02 ± 2.07 6.45 ±1.81 0.136
O2 extraction (ml/100ml) 13.66 ± 3.31 14.63 ± 4.38 19.52 ± 6.53 0.008
Slope      
ΔQ’/ΔV’O2 (L/L) 5.84 ± 1.82 5.38 ± 1.63 4.01 ± 1.26 0.043
  1. Demographic data and results of cardiopulmonary exercise tests in patients with chronic fatigue syndrome, idiopathic chronic fatigue and healthy humans during rest, at the anaerobic threshold and maximal workload. BSA: body surface area, HR: heart rate, V’O2: oxygen uptake, V’O2/pred.: oxygen uptake as percentage of predicted, SVI stroke volume index, ΔQ’/ΔV’O2: increase of cardiac output relative to the increase of oxygen uptake.