Table 4.

PCA component matrix (peak values)

	Component
	1	2	3
$$\dot{\mathbf{V}}{\mathbf{O}}_{2\mathbf{peak}}$$	0.950	0.014	0.081
$$\dot{\mathbf{V}}{\mathbf{O}}_{2\mathbf{peak}}$$	0.859	−0.217	−0.088
$$\dot{\mathbf{V}}{\mathbf{O}}_{2\mathbf{peak}}/\mathbf{H}{\mathbf{R}}_{\mathbf{peak}}$$	0.853	−0.182	0.305
$$\dot{\mathbf{V}}{\mathbf{E}}_{\mathbf{peak}}$$	0.720	0.147	−0.518
RR peak	−0.305	0.362	−0.665
HR peak	−0.180	0.406	−0.304
BRR	−0.197	0.675	0.688
(V d /V t ) peak	−0.341	−0.545	0.301
FEV 1	0.432	0.817	0.214