Why do in stumble and sometimes actually fall down when standing up after i've been sitting? it's not like i black out or even feel lightheaded. i'm fully aware of what is happening, but can't prevent it. it just like my legs go weak suddenly and can't su

Hello. : Hello. I can't diagnose your symptoms. However, paradoxically; even though you have hypertension, you may also be having some problems with hypotension. Sometimes when going from a sitting to a standing position, gravity causes blood to pool in your feet and lower legs. This results in less blood going to your brain and thus lightheadedness. This can cause you to feel weak. If this is occuring, it is called orthostatic or postural hypotension. It can be dangerous because you could actually fall and get hurt. Recommend that when going from lying to sitting or sitting to standing that you do so slowly. Additionally, please let your doctor know, in case any of your medications needs adjusting. Hope this answers your question. Take care.