My guidelines for interpreting CPETs originally started as notes to myself about what needed to be on the report and what the normal values were. They grew into a more formal set of instructions that were given to the pulmonary fellows when they were reviewing CPETs. Lately I’ve been reviewing them and re-reading the source material in order to make sure what I had written was still correct and so I could add references.
I tend to focus on one aspect of testing at a time and noticed while reviewing material that the measurements made at peak exercise or anaerobic threshold are almost always considered to be the most important test values. This is true to an extent, but information gathered both before and after testing is also important. In particular, after exercise has ended, during the recovery period, there are several measurements that should be made routinely and are diagnostically significant.
Heart rate recovery (HRR)
When exercise ends, an individual’s heart rate should start decreasing from its peak value. The heart rate recovery (HRR) is the difference between the heart rate at peak exercise and at some interval, usually 1 minute, post-exercise. The rise in heart rate during exercise is due to a combination of parasympathetic withdrawal and sympathetic activation. Vagal reactivation is the principle determinant of heart rate recovery after exercise and a reduction in the heart rate recovery (HRR) indicates a decrease in vagal tone specifically, and parasympathetic tone generally.