Supposedly I should be able to do a "Long, Slow Run" staying in Zone 3 of Heart Rate Reserve (146-160) but walking fast doesn't get my heart up high enough, and running at my slowest possible pace will bust the Zone 3 limit within a minute.
I did a Zone 3 run/walk for 5k and ended up running 16 short intervals. My heart rate went up at 12 bpm each time I started running, and would fall at 12 bpm when I started walking. I guess that shows symmetry in the sympathetic and parasympathetic response. Supposedly a large, quick response to stress is good, but my recovery is only borderline sufficient.
After a year of running, I have not seen any change in the recovery rate, Sometimes, because my heart rate will go up a beat or two right after I stop running, the 1 minute recovery will be only 5-8 beats but the 2nd minute recovery will be 12-14 bpm.
