Thank you all for the advice, tips, and so forth. Throughout the day today I would stop myself and ask, "What if I were sitting in meditation right now? Would my heart beat so powerfully?" This sort of seemed to draw me back to mindfulness of the body and awareness of my heartbeat. When I did sit for meditation yesterday evening, I did not have near as much trouble with a powerful heartbeat. It arose a few times, but passed away much sooner than previously. It would stay for several minutes in the past.
I think that I am going to start doing several (3-4) short sessions of mindful walking throughout the day. And I have a greater appreciation for mindfulness awareness in daily activity than I did before posting this.
I am certainly not obese. If anything, I am underweight. I suppose that it might be an issue of poor health in a different area. I am due for a checkup with my Dr. so I will bring it up with him soon enough.
Also, I agree with your other comment about coffee and stimulants. I drink too much coffee as it is. I cannot remember exactly how long it had been since having a cup before I sat when I first noticed this, but I am sure that it is related.
I probably should be getting a bit more exercise. I used to ride my bike a lot, but I had to stop for a little bit because of a problem with one of my legs getting abnormally stronger than the other. This is a somewhat common problem among cyclists who ride great distances. I will probably get a few rides per week once the weather starts to get nicer around here (Midwestern USA).
I identify with what you said concerning to not noticing the heartbeat except when meditating. This was something I was able to notice today when I would stop and allow myself a short period of mindfulness of body. I also think that this made me better prepared for when it arises during meditation.
"however long that might take." Yes! Thanks for that.
I would agree that this has something to do with excitement. I do find that I am sort of racing down to the cushion to gets some quality time. Also, it has been a long time since I have sat for lengthy periods of meditation. So, I am pretty sure that there is also some emotional animation occurring.
I think I may not have been clear when I wrote my original post. It does not seem like my heart is beating more beats per minute. Rather, it does feel like it is beating more forcefully. Thanks for the post.
All outward-going knowing
--Upasika Kee Nanayon