Figure 1.

Representative subject #6 (male, 56 years). Exercise response variables in a representative subject at SL (empty circle) and at HA (filled circle). The black arrow indicates VCP; the white arrow indicates the θ_L. A single breakpoint in the ${\dot{V}}_{\mathrm{E}}/\mathrm{HR}$ at VCP was clearly identifiable, both at SL and at HA (see text for further comments).