Hello! Thank you for asking on HCM! I read your question carefully and would like to explain that your symptoms seem to be related to low blood pressure or orthostatic hypotension. A chronic anemia could also mimic this clinical scenario. Have you measured your blood pressure during these episodes? I recommend to closely monitor your blood pressure during sitting and standing up position. A decrease more than 20mm HG in your systolic blood pressure during standing up position, compared with sitting position would indicate an orthostatic hypotension. I would advise to consult with your GP for a careful physical examination, a resting ECG and some blood lab tests: - complete blood count - fasting glucose - blood electrolytes - kidney and liver function tests - thyroid hormone levels to exclude other possible metabolic causes. A head up tilt tests would be necessary to rule in/out a possible orthostatic hypotension. Meanwhile, I recommend taking plenty of fluids (water, juices) and avoid dehydration. Hope to have been helpful! Greetings! Dr. Iliri