A research study conducted by exercise scientists at the University of New Hampshire confirms the effectiveness of the low-tech "talk test" for measuring exercise intensity.
In the study, researchers asked participants to read the Pledge of Allegiance while exercising and then rate their comfort level while doing so. At the same time, they monitored heart rate and maximal oxygen consumption (VO2 max). The point at which participants began having difficulty speaking correlated with reaching the upper level of exercise intensity guidelines.
While the study reinforced the general rule to exercise at a level where speaking is not difficult, it also gave new insight into how the test compares to two other measures of exercise intensity. Previous studies have shown that the talk test relates well to the ventilatory threshold, but the New Hampshire study was the first to also gauge its effectiveness in comparison to the lactate threshold. Scientists were surprised to find that the talk test related better to the lactate threshold than the to ventilatory threshold, and that at the point at which participants in the study began to have difficulty speaking, they were nearing their lactate threshold, which has been shown to be a better predictor of performance than the ventilatory threshold.
This new finding can be useful to athletes seeking to improve endurance performance, which is done by exercising at or near the lactate threshold. According to the research, by simply using the talk test athletes can accurately estimate the appropriate intensity for increasing endurance.