Table 1.

Responses to Maximal Tolerable Interval Exercise (IE) and Constant-load Exercise (CLE) in Patients with Severe COPD

	End of IE	End of CLE
Total Exercise time (min)	32.7 ± 3.0	1 0.3 ± 1.6*
VO2 (L/min)	0.81 ± 0.05	0.94 ± 0.07*
VCO2 (L/min)	0.75 ± 0.04	0.95 ± 0.07*
VE (L/min)	33.1 ± 1.5	38.4 ± 2.2*
VE/MVV %	76 ± 4	85 ± 3*
VT(L)	1.01 ± 0.05	1.14 ± 0.06*
VT/IC %	66.4 ± 2.0	75.2 ± 1.7*
IRV(L)	0.58 ± 0.06	0.38 ± 0.03*
IRV%pred. TLC	8.9 ± 0.8	5.9 ± 0.5*
Paco2 (mmHg)	44.0 ± 1.3	45.4 ± 1.2*
pH	7.38 ± 0.06	7.34 ± 0.07*
VD(L)	0.48 ± 0.02	0.53 ± 0.02*
Arterial Lactate cone. (mMol/L)	3.89 ± 0.36	5.81 ± 0.41*

Modified from the European Respiratory Society.²⁶ Data are presented as mean ± SEM. VO₂: oxygen uptake; VCO₂: carbon dioxide output; VE: minute ventilation; MVV: maximum voluntary ventilation; VT: tidal volume; IC: inspiratory capacity; IRV: inspiratory reserve volume; PaCO₂: arterial carbon dioxide tension; VD: physiological dead space; cone: concentration.

^*Significant differences (p<.05) between IE and CLE