According to this article:
https://www.livestrong.com/article/4...eturn-to-base/
"Measure your heart rate again a few seconds before you stop your workout. Then keep measuring at intervals of about one minute. If your heart rate is 190 during exercise and your resting heart rate is 80, it could take you several minutes for your heart rate to return to normal."
According to this article:
Heart Rate and Health | Berkeley Wellness
"Your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. This “recovery heart rate” is measured as part of an exercise stress test."
Here's another article which you might want to read:
https://www.webmd.com/heart-disease/...ousand-words#1