Fig. 3

Schematic illustration plots of ̇V̇CO₂ against V̇O₂ a during exercise and b post-exercise of a younger female adult, and c during exercise and d post-exercise of a middle-aged female adult e hypothetical 3-dimensional graph across time (during CPET and post-CPET), comparing one younger and one middle-aged adults, where a to d are expressed in a 3-dimensional graph across time (illustration not drawn to scale). Dotted lines represent aerobic threshold of a younger (a; blue dotted line) and a middle-aged adult (c; red dotted line). Proposed recovery aerobic threshold of a younger (b; blue dotted line) and a middle-aged female adult (d; red dotted line) (unpublished results)