Why Do I Get Dizzy When I Stand Up?

Getting dizzy when you stand up is not an unusual phenomenon. It usually lasts just a few seconds and then passes, but if you have really low blood pressure or are dehydrated, then it will last longer. So why do I get dizzy when I stand up? It is related with a complex system of blood vessels that will be explained in this article.

Why Do I Get Dizzy When I Stand Up?

The sensation of feeling dizzy when you stand up has the medical name of "orthostatic hypotension." Simply put, orthostatic hypotension is the phenomenon that happens when gravity takes hold of our circulatory system and causes blood from the veins in your head to rush out of the head, making the brain feel dizzy for a while until the blood from the arteries can replace the blood lost by the veins, restoring the blood pressure in the brain to its normal level. All in all, feeling dizzy is a common complication of having a too low blood pressure in the brain.

Common symptoms of having too low a blood pressure in the vein include feeling dizzy, light-headed, and having blurry vision. You may feel temporarily confused and a little bit nauseous. In some cases, you can sustain tremors of the muscles and, if the low blood pressure lasts for more than a few seconds, you can actually faint, although you will regain consciousness when you reach the ground.

It’s all a matter of gravity. When gravity takes hold upon standing up, about 800 cc of blood travel from the top parts of the body down to the legs, leaving more venous pressure in the legs than that exists in the brain. Fortunately, we are made with baroreceptors, which are sensors in the carotid arteries and in the aorta that sense that the blood pressure is low and put the heart on high alert to pump out more blood faster. The blood vessels located in the abdomen and legs will constrict to push blood upward to the brain. This all happens in a matter of seconds.

Underlying Causes of Orthostatic Hypotension

While you are wondering "Why do I get dizzy when I stand up?" you may be also wondering if there is anything wrong with you that needs medical attention. Fortunately, this is rarely the case and there can be reasons behind the orthostatic hypotension that are perfectly explainable.

  • Low blood volume. If your blood volume is low, such as with dehydration or acute blood loss, you will not have enough blood in your brain when you stand up and you will feel dizzy. Fortunately, these things can be corrected with getting extra fluids and taking iron to build up your blood supply.
  • Diseases. Several diseases are associated with orthostatic hypotension. These include an adrenal gland deficiency (called Addison’s disease), diabetes, pheochromocytoma (a tumor on the adrenal gland), diabetes mellitus, anorexia nervosa, Parkinson’s disease, some types of neurological disorders, quadriplegia and paraplegia. Even inner ear problems can contribute to feeling dizzy upon standing.
  • Medications. You can have orthostatic hypotension as a result of taking some kinds of medications. For example, tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs), marijuana, and alpha blockers (which blood bleed vessel constriction), are all medications that can lead to a drop in blood pressure upon standing up.
  • B12 deficiency anemia. B12 deficiency is when the gastrointestinal tract does not absorb vitamin B12. This causes anemia that, like other causes of anemia, can decrease the amount of oxygen reaching the brain, especially when you stand up suddenly.

How to Relieve the Dizzy Feeling When Standing Up

Rather than worrying about "why do I get dizzy when I stand up?" consider these home remedies that you can use to prevent or treat orthostatic hypotension. For example:

  • Increase the salt and water in your diet in order to have more blood volume all around. Stay as hydrated as possible. This means putting more table salt on the food you eat. It can raise your blood pressure naturally by acting on the kidneys.
  • Eat smaller meals. When you eat too large meals, the blood pools in the abdomen and there is less in the rest of the body. Try eating six small meals per day instead of three larger ones.
  • Get some exercise. Exercise tones the arteries and veins of the body so that there is less pooling of blood when you stand up. You need the strength of your lower calf muscles in order to squeeze the veins so that the blood gets to your head faster and less venous extremity pooling occurs.
  • Don’t bend down to pick up things off the floor. When you stand up, this will cause the blood to rush from your brain. Instead, squat when picking up things and get up slowly. The squatting will keep the blood from pooling in your veins.
  • Wear lower extremity compression socks or binders for the abdomen. The stockings can be knee high or thigh high stockings. They take the place of weak muscles so that blood cannot pool in the lower legs. Use this along with an abdominal binder, which prevents pooling of blood in the abdomen. Compression stockings and abdominal binders should be used together.
  • Get up very slowly. This gives the baroreceptors a chance to work and will allow your system to equilibrate as you stand. It takes a few seconds for the baroreceptors in the neck arteries to sense a low blood pressure going to the brain, so it can send out signals to the body to raise the blood pressure.