What POTS can involve
POTS — postural tachycardia syndrome, often written PoTS — involves the autonomic nervous system, the part of the body that quietly manages heart rate and blood pressure. For many people symptoms appear or build when upright: a racing heart, dizziness, near-fainting, brain fog, heat intolerance and a heavy fatigue — and often ease when lying down.
It is a real, recognised condition. It is not anxiety, and it is very often mistaken for it. A record of what happened, when, and what you were doing at the time is one of the few things that speaks for you when a reading taken sitting down looks normal.