What is meant by the aerobic and anaerobic thresholds? What are the ventilatory thresholds (VT1, VT2)?

What is meant by the aerobic and anaerobic thresholds? What are the ventilatory thresholds (VT1, VT2)?

Explanation of thresholds: Aerobic and anaerobic thresholds and ventilatory thresholds

The individual anaerobic threshold is the performance and pulse range in which the body switches from an oxygen-saturated situation to a phase of oxygen debt. Sports scientists differentiate between the aerobic and anaerobic training range. The anaerobic threshold is a crucial parameter for developing a well-founded training plan. Incidentally, this threshold is also referred to as the transition from fat metabolism to carbohydrate metabolism.

The 1st ventilatory threshold (VT1) describes the aerobic exercise intensity above which there is an increased consumption of carbohydrates during muscular energy production. This leads to an initial measurable increase in lactate formation in the muscles and thus to an increase in CO2 exhalation. The first ventilatory threshold (VT1) is also known as the aerobic threshold. VT1 marks the transition from the ET1 range to the ET2 range.
 
The 2nd ventilatory threshold (VT2) describes the intensity of exercise from which the lactate-induced acidification of the body can only be compensated for by a further significant increase in the work of breathing with exhalation of carbon dioxide (CO2) and an increase in the respiratory minute volume. From this point onwards, the body obtains its energy almost exclusively from carbohydrates and enters an oxygen deficit. The 2nd ventilatory threshold (VT2) can be equated with the individual anaerobic threshold.