Table 1. Subject characteristics of basic physical findings, lung function
Completed Not-Completed
n 17 10
Age, years 30.8 ± 3.0 26.9 ± 3.3
Sex (male/female) 15/2 9/1
BMI, kg/m2 23.1 ± 0.8 21.1 ± 0.9
%VC, % 91.2 ± 2.5 91.9 ± 4.9
%FEV1, % 88.9 ± 2.4 91.0 ± 4.9
FEV1/FVC, % 86.7 ± 2.2 87.7 ± 2.4
Notes: Values represent the means ± standard error of the mean. The completed group is who continued to exercise for 20 minutes in constant load exercise test, and the not-completion group is who could not that.
Abbreviations: BMI, body mass index; VC, vital capacity; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity.
Table 2. The comararison of metabolic indexes in incremental load exercise test
Completed Not-Completed
N 17 10
Vo2, ml/kg/min 43.4 ± 2.1 47.5 ± 3.0
Vco2, ml/kg/min 54.2 ± 2.5 60.1 ± 4.0
RER 1.25 ± 0.02 1.28 ± 0.02
ETo2,% 14.1 ± 0.6 15.2 ± 0.8
ETco2,% 5.7 ± 0.6 5.4 ± 0.6
VE/ Vo2 37.8 ± 0.9 39.1 ± 1.5
VE/Vco2 30.2 ± 0.6 30.6 ± 1.1
VE, L/min 107.6 ± 5.3 113.2 ± 6.7
VT, L 2.3 ± 0.1 2.5 ± 0.2
VD/VT 0.26 ± 0.01 0.25 ± 0.02
RR, breaths/min 47.2 ± 1.4 45.9 ± 2.3
PR, beats/min 148.1 ± 40.2 151.5 ± 37.2
Spo2, % 91.2 ± 4.0 90.7 ± 7.4
AT point, ml/kg/min 26.0 ± 1.1 25.7 ± 1.3
RC point, ml/kg/min 37.2 ± 1.6 41.2 ± 2.6
Minimum VE/Vco2 27.3 ± 0.5 26.8 ± 0.7
Notes: All values of metabolic indexes except for AT point, RC point and minimum VE/ Vco2 are at peak of exercise. Values represent the means ± standard error of the mean. The completed group who continued to exercise for 20 minutes in constant load exercise test and the non-completion group who could not that.
Abbreviations: Vo2, oxygen uptake; Vco2, carbon dioxide output; RER, respiratory exchange ratio; ETo2, end-tidal oxygen, ETco2, end-tidal carbon dioxide; VE, ventilation; VT, tidal volume; VD, dead-space gas volume; RR, respiratory rate; PR, pulse rate; Spo2, percutaneous oxygen saturation; AT, anaerobic threshold; RC, respiratory compensation.
Table 3. The comararison of metabolic indexes in constant load exercise test
Completed Not-Completed
N 17 10
Endurance time, min 19.5 ± 0.1 9.9 ± 2.0
Vo2, ml/kg/min 35.2 ± 1.8 41.5 ± 2.6
Vco2, ml/kg/min 34.3 ± 1.9 42.7 ± 3.1*
RER 0.97 ± 0.01 1.01 ± 0.02*
ETo2,% 14.1 ± 0.6 15.2 ± 0.8
ETco2,% 5.7 ± 0.6 5.4 ± 0.6
VE/Vo2 33.3 ± 5.0 35.9 ± 4.9
VE/Vco2 34.6 ± 4.1 35.4 ± 3.6
VE, L/min 76.4 ± 4.1 92.2 ± 7.0*
VT, L 1.76 ± 0.08 2.19 ± 0.20
VD/VT 0.27 ± 0.02 0.26 ± 0.03
RR, breaths/min 43.9± 1.9 43.7 ± 3.8
PR, beats/min 159.8 ± 6.3 177.4 ± 4.2
SpO2, % 91.2 ± 1.0 90.7 ± 2.3
Minimum VE/Vco2 27.0 ± 2.9 29.5 ± 2.6 *
Notes: All values of metabolic indexes except minimum VE/Vco2 were at peak of exercise. Values represent the means ± standard error of the mean. *p < 0.05 vs. the completed group. The completed group who continued to exercise for 20 minutes in constant load exercise test and the non-completion group who could not that.
Abbreviations: Vo2, oxygen uptake; Vco2, carbon dioxide output; RER, respiratory exchange ratio; ETo2, end-tidal oxygen, ETco2, end-tidal carbon dioxide; VE , ventilation; VT, tidal volume;VD, dead-space gas volume; RR, respiratory rate; PR, pulse rate; SpO2, percutaneous oxygen saturation; AT, anaerobic threshold; RC, respiratory compensation.
Table 4. Single logistic regression analysis to predict completed exercise in constant load exercise test.
Vriable Odds ratio 95%CI P-value
Minimum VE/Vco2 0.707 0.50 - 0.10 0.05
RER 0.001<0 0 - 2.52 0.64
VE 0.96 0.92 - 1.00 0.06
Note: Independent variable was completed or not-completed group as categorical variable.
Abbreviations: 95%CI, 95% confidence interval; VE /Vco2, minute ventilation/carbon dioxide output; VE , minute ventilation.