Dysautonomia... I hadn't heard of this term until I started reading more about Ehlers-Danlos Syndrome (EDS). Apparently, it's a group of syndromes that impact your bodies ability to self-regulate - heart rate, blood pressure, etc. I have two - inappropriate sinus tachycardia (IST) and orthostatic hypotension (OH).
The syndrome of IST is defined as a sinus heart rate over 100 beats per minute (bpm) at rest, with a mean 24-hour heart rate of over 90 bpm not due to identifiable causes, and is associated with distressing symptoms of palpitations. IST it is estimated to impact around 1.2% of the population.
OH is defined as a decrease in systolic blood pressure of 20 mm Hg or a decrease in diastolic blood pressure of 10 mm Hg within three minutes of standing when compared with blood pressure from the sitting or supine position.