Feeling lightheaded every time I get up

I am at 2100 calories for the day, and I was at 1800something yesterday for food, which is my norm. I have noticed the last few days, every time I stand up, I get light headed and feel like fainting.

Does anyone have an idea of why?

Are you sitting for long, extended periods of time? How long have you been eating at the 1800-2100 level? Are you working out a lot? Is this a new diet?

You may want to go check in with your doctor, but I know when I a sedentary for a long time (seated or laying down) and first get up, I'm kind of lightheaded. My doc says it has to do with low blood pressure, but I would highly recommend you talk to your doctor about this rather than looking on MFP.

That happens to me sometimes because my blood pressure is often very low. I've actually had doctors recommend that I eat more salt to help. Usually it only happens when I've been lying down. I don't normally consume a ton of salt, so adding some sodium to my diet was pretty easy.

I think it's worth talking to a doctor if it's happening so often and is unusual for you. I've had my minor issues my whole life.

No major diet changes, I have been eating around 1800-2100 calories per day for months. Typically, when I lay down it is for 20 mins or so...then I get up and I just get dizzy. I knew this could happen on a low calorie diet/high deficit. My deficit is typically between 500-750 per day.

I have just noticed it happening more frequently (some days are better than others). If it lasts until monday, I will go see a doctor.

If it is orthostatic hypotension, which it sounds probable, it is more and issue of how hydrated you are and less to do with how many calories you're intaking. Have you been drinking adequately those days?

Blood pressure is actually a measure of how hard your blood is pushing on the inside of your blood vessels. The top number is the measure in the full strength of a heartbeat, and the bottom number is the measure while the heart is at rest. If you imagine the vessels like a hose, the more fluid/pressure you put behind the hose, the harder the pressure is inside the hose and forced out the end. If you have a low blood volume (caused by dehydration), you are more likely to experience orthostatic hypotension. Orthostatic means body position and hypotension is low blood pressure.

We recommend that people with this problem sit up with their feet off the side of the bed for a few minutes before they go to stand. Drink plenty of water and stay hydrated. If you believe you are fully hydrated and still have problems with this, it wouldn't be a bad idea to visit your doctor.

Also, be careful with taking potassium supplements. The blood values for it have a very small window for error and it can cause heart dysrythmias. You shouldn't need more than eating a couple bananas or some extra green, leafy veggies unless you've had extensive diarrhea lol

Besides the hydration thing multiple people have mentioned, a quick trick if you feel lightheaded upon standing is to flex the muscles in your legs and core for a few seconds. Muscle contraction will decrease pooling of blood in the legs and increase venous return to your heart and help to maintain blood flow to your brain. Same trick fighter pilots use to help them from blacking out in high G-forces.

I get this pretty often and I have been since I was about 14. It's from low blood pressure (doesn't help that I'm also a tad tall/lanky). Since your blood pressure is low, if you move quickly and change your elevation after being sedentary it takes a moment for your body to catch up and move more oxygen to your brain. I've heard you can avoid it if you flex and unflex your muscles a few times before getting up. Getting more salt and other electrolytes, along with water, will also help. The good news is you probably don't have brain cancer, even if WebMD says otherwise Obviously if the above advice doesn't alleviate it some, you might want to consult a doctor.

It's been happening to me for a few years. I often times completely lose vision/black out and have to hold something for a few seconds.

try eating more salt. "Hydration" is about electrolytes not just water.