Originally Posted by
bpcyclist
Thanks very much, that is very interesting to me. I think I'll try it. The only thing I might add is that these numbers can be quite fluid (pardon the pun), depending on overall volume/fluid status. Did you get up and chug a half-gallon of skim milk at 3 AM? Did you not only not eat dinner, but also for whatever reason have not had any meaningful fluids in twelve hours? So on and so forth. Anyhoo, all this intravascular volume stuff is important to bear in mind whenever you are looking at any kind of heart rate numbers.
I don't see a difference from food or fluid intake. OTOH my habits are very regular. I always eat and drink about the same amounts at the same time from evening on. On the bike, I'll see increased HR from dehydration but that goes away quickly with rehydration. I will sometimes see slightly anomalous MRHR numbers, but they don't seem to affect the orthostatic. I don't use any one thing as gospel.
If anyone wants to try that Elite HRV app, the best tell I get from that app is to take it standing for 5 minutes (Open Reading), then look at my HF power. That seems to be the one thing which fluctuates most reliably with training or other physiological stress. That number going through the floor was my first warning that I was coming down with p
olymyalgia rheumatica, long before it was diagnosed. HF power correIates with the happiness of one's parasympathetic system. I take my Morning Readiness, then the Open Reading. I add the two RMSSDs together and record that.