VT1 is called the first ventilatory threshold. It is a marker of intensity that can be observed in a person’s breathing at a point where lactate begins to accumulate in the blood and breathing becomes harder, it is the point which it becomes uncomfortable to speak. In well trained athletes VT1 is roughly the highest intensity that can be sustained for up to two hours of exercise.
VT2, or the second ventilatory threshold, is a higher marker of intensity than VT1. At VT2, lactate has quickly accumulated in the blood and the person needs to breathe heavily. At this rapid rate of breathing, the exerciser can no longer speak. In well trained athletes VT2 is the highest intensity that can be sustained for 30-60 minutes of exercise.
In a variety of studies conducted it was found that in general, serious athletes spend 70-80% of their time training at intensities less than VT1, 10-15% of their time at intensities between VT1 and VT2, and approximately 5-10% of their time training at intensities above VT2.
It has also been found that a simple way to figure out which intensity you fall into during exercise is the “Talk Test.” If the athlete can speak comfortably, they are almost always below VT1, the point at which it becomes noticeably harder to speak is between VT1 and VT2, and the point at which it becomes too difficult to speak is the point we reach VT2.
These different thresholds can be broken into “Zones” giving us three separate training zones we can use during our training:
