Not really sure how to take a baseline, but improving this time seems like a great goal.
The heart rate two minutes after exercise is referred to as the recovery heart rate. This is the most common measurement in determining cardiovascular fitness. To test for improvements, record the working heart rate during exercise, then record recovery heart rate at the two-minute mark. Subtract the two-minute recovery rate from the working heart rate to determine a baseline for improvement. For example, if working levels were 150 beats per minute and the two-minute recovery rate was 95, then 55 is the recovery heart rate.
So improving “TMR” is the goal. It seems like the best way to measure it would be on a stationary cycle. Not sure if one should hit a target like 140 for x minutes, then stop or what. Also doing this as interval training is the overall goal.