I do have history of vertigo and low blood pressure. is it normal that my head gets dizzy for a few second once i get up from a sitting position? mostly when i m kneeling on the floor. also, when i lie down flat on bed...my head can feel a bit dizzy. but

No: But with the history you describe not unexpected. Would also be concerned about benign positional vertigo. This is a benign condition that can be evaluated and treated with some simple maneuvers called Epley maneuvers. You can Google a video search or YouTube search this and try them on your own to see if they help. However, continue to do what you're doing, change position slowly to prevent dizzi

Dr Pack agreed

Yes orthostatic: This is probably orthostatic hypotension - the body needs to adjust when you move positions. I suspect this si why you feel dizzy. Your physician can clarify and be certain that your blood pressure is Ok Also your labs like blood counts are all OK and that there are not any circulatory or inner ear issues that could also be playing a role.

Dr Munshower and another doctor agreed

Probably normal: However, you want to visit your doc and ask about a tilt test, meaning you are a little upside down and then your position will go up. No big deal but better be safe. Good luck.

Dr Vallury agreed

Fluid status.: It's common for one to feel lightheaded upon standing when one is dehydrated, and there are other causes as well. Check your blood pressure sitting and standing; if it falls below 100 systolic (the upper number) with standing, try drinking a tall glass of water, then repeat the BP check sitting and standing. If this continues to recur, see your physician for an exam.