Final answer:
The Second Ventilatory Threshold, or VT2, is a point during exercise where lactic acid accumulation leads to fatigue. It is used to determine training intensity zones for athletes.
Step-by-step explanation:
The Second Ventilatory Threshold, also known as VT2, is a critical point during exercise where lactic acid begins to accumulate in the muscles and blood. At this point, the body's ability to remove lactic acid is no longer able to keep up with its production, leading to fatigue. VT2 is an important marker of endurance performance and can be used to determine training intensity zones for athletes.