Special Needs to Prescribe Exercise Intensity for Scientific Studies

Figure 4

Schematic representation of first- and second- turn points of selected variables (La blood lactate concentration; VE: ventilation; VE/VO₂: equivalent for oxygen uptake; VE/VCO₂: equivalent for carbon dioxide output; HR: heart rate; 𝐵_𝑓: breathing frequency) and distinct phases (Ph 1–3) of energy supply determined from young healthy male subjects. Ph 1: no increase of blood lactate concentration above baseline during constant load exercise. Ph 2: increased but steady state blood lactate concentration during constant load exercise. Ph 3: continuous increase of blood lactate concentration during constant load exercise leading to early termination of exercise.

(a)

(b)

(c)

(d)

(e)

(f)