Hi larryrr and thanks for sharing your experience with us. One of the first responses of the body to low oxygen is an increased heart rate. In the most general of terms, if your shortness of breath is due to a low oxygen level, it might explain your elevated pulse rate until you catch your breath and normalize. Please remember this is meant to be a possible explanation for what you describe. I would suggest you discuss this further with your physician if these symptoms you describe persist or worsen.
All the best,
Leon (site moderator)