Hello! Welcome on Healthcaremagic! I read carefully your question and understand your concern. Orthostatic hypotension can mimic this situation. Electrolyte imbalances like high potassium levels (caused by candesartan) can trigger this situation too. For this reason, I would recommend checking your blood pressure values in sitting and standing up position. If there is a drop in your blood pressure in standing up position orthostatic hypotension could be the cause. It is also necessary checking your potassium plasma levels, although it is not typical for high potassium levels to cause symptoms which are modulated by standing up. Hope you will find this answer helpful! Best wishes, Dr. Aida