What your are describing is what we call orthostatic pre-syncope. This refers to symptoms of lightheadedness that sometimes precede passing out that occur when one stands up. When you stand up, gravity pulls blood that is heading towards your brain down towards your feet. This temporary decrease in blood flow to the brain makes you feel lightheaded and can even result in passing out. This happens when the normal nervous system mechanism to prevent blood from falling from the head doesn't work properly. This can happen when you are dehydrated, or when your blood volume is low for another reason. Staying well hydrated may help you. On the other hand, certain neurological diseases can cause this. One of the most common cause is cardiovascular system issues such as heart valve disease, but this would be quite unusual in someone your age.
I suggest that you schedule an appointment with your primary care physician (such as a family doctor
or internal medicine doctor
). He or she can evaluate your blood pressure and pulse when you are sitting versus standing (this is know as getting your orthostatic vital signs). If an abnormality is really found, then you may warrant referral to a cardiologist
for a specialist evaluation. Good luck.