While this hasn't happened to me yet, i wonder if you're getting pooling of blood in the veins of your legs, which your body doesn't have time to adjust for when you get out of the car. Try this old French foreign legion trick - the legionnaires were asked to stand still at attention for long periods in the desert heat. The young recruits were always the ones who fainted first in the heat until someone from the old guard took pity on them and revealed the secret - all the while they were standing there, the old soldiers were isometrically flexing and relaxing the muscles of their calves and thighs, producing return of blood flow back to the heart. They seemed to be still because with long pants on no muscle contraction was seen. also a good idea to isometrically work the muscles of your legs on plane flights to reduce the risk of deep vein thrombosis. let us know if this works!

I did .,..very slow and then leaned against car for several seconds before I went to walk in hospital to have some blood work done. I took about 6 steps and out I went. When I came to there was about 15 hospital employees standing over me. It only happens after I get out of a moving vehicle.

When you stand up try doing it a little slower

lisa,
it's true . You have to let go of your feet and wait a moment

Excellent question. Prior to my STN-DBS surgery, I'd be standing in the Patio doorway and had fallen to the rear on a couple of occasions.