From my own experience, my heart rate is different depending on many factors, morning is always the worse and afternoons the best generally speaking. I think that's due to the fact that in the evening I have had a full day of drinking water and the meds etc. (also possibly hyper, having these tests to noarrow down which pots currently)
I no I'm having a bad day or a "flare" as it's called, when even laying down my heart is racing. Nausea is worst also in the morning and that "usually" fades by lunchtime.
Tilt table test should be enough to diagnose you, your heart rate shouldn't change to much from day to day, mine is always roughly 80bpm sitting and 120bpm standing (that's without meds) and that's day in day out. As I said a bad is about 140 standing and 115 laying down (not fun). You may also consider a 24heart rate monitor and ecg stress test, mine was diagnosed while doing the stress test, lol I literally stood up and the doctor was like "huh" then went onto the treadmill for 5mins of light walking and the doc said "yep, all good, Iv seen enough". Anyway good luck with the test, hope you get some answers
contact DR JAMAR MALEEK HOME OF HERBAL HEALING TODAY ON ***@**** for any kind of sicknes you are facing today,i was cured from genital herpes by his herbal remedy
you can also call him on
+2348050676586 or whatsapp him today