TABLE 2.

Regression relationships between the inspiratory pressures generated (from Figures 5, 6) when inspiring against a graded inspiratory resistive load (X) and the additional physiological variables (Y) measured (included values were averaged across each inspiratory loading period).

	Breathing rate (bpm)	Breathing depth (au)	Pressure of end-tidal CO2 (%)	Pressure of end-tidal O2 (%)
Regression R2	0.83	0.93	0.99	0.94
Coefficient	−4.12	0.11	−50.11	13.51
Degrees of freedom (total)	5	5	5	5
P value	0.01	<0.01	<0.001	<0.01