LA Weight Loss - Light headed, almost blacking out

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07-15-2009, 11:43 PM
Hello everyone,

This is my first post here, and I am happy to have found such a great resource.

Lately, I have found that when I stand up quickly my eyes start to black out and I feel as though I'm going to pass out. This is weird to me, as I definitely feel as though I've been eating enough calories! I'm eating at least 1200 a day, usually much more (1500+). It especially happens to me right after exercise (ie walking up a big hill, cardio machines, etc).

Has anyone had experience with this feeling as well? Do you think it could be due to too big of a caloric deficit? or perhaps I'm not hydrated enough? Something else?

I haven't passed out, it just feels like it. Usually if I try and breathe faster during an episode the feeling goes away faster.


07-15-2009, 11:45 PM
Do you eat before you exercise? Do you have low blood pressure? You might want to eat some sodium or electrolytes before you exercise.

I have hypoglycemia and low blood pressure which both can cause what you are describing.

Suzanne 3FC
07-15-2009, 11:48 PM
Please ask your doctor about this. I agree with nelie, it sounds like blood sugar or blood pressure. Your doctor can test you and find out what the problem is, so you can treat it as quickly as possible. It definitely indicates a problem. Try to keep a log of what you eat and show your doctor as well.

Good luck :)

07-16-2009, 12:12 AM
Sounds like you could be dehydrated. I get dizzy and light-headed if I don't drink enough water.

07-16-2009, 12:15 AM
Sounds like low blood pressure (I have this)....I would bring this up to your doctor!

07-16-2009, 12:17 AM
I have something like that and it's called Postural Hypotension and it's generally caused by being dehydrated.

07-26-2009, 02:45 PM
I get this really bad when I'm dehydrated I had it the other day horrible. I live in Las Vegas and it is hard to drink enough. I drank some gatorade and got better.
But you should check with your Dr you could have blood pressure problems.

07-26-2009, 03:10 PM
Number of reasons:
blood sugar

MOST likely something called POSTURAL HYPOTENSION -- characterized by a faint/dizzy feeling when standing from sitting, or from lying down to coming upright. If it was low blood sugar, it would happen without regard for your posture. There may be an anxiety component in that if you are afraid you'll feel faint especially during exercise, it will magnify any blood pressure issues (not that you need treatment for anxiety, just saying it doesn't help, that's all).

You should see your MD about it. If it is a mild case, then no treatment is generally required. But if it is severe, the underlying causes should be identified. It could be as simple as dehydration.


07-26-2009, 05:54 PM
This used to happen to me at the start of my diet as well - I was eating ~1200 calories on average, some days less (I zigzag). I eased off the exercise to allow my body to adjust to the lower food intake, slowly upped the intensity over a 1-2 week period. Also drank lots of water and made sure to take vitamin and calcium supplements since lightheaded-ness can be caused by mineral deficiencies as well.

07-26-2009, 06:02 PM
Similar issue here mine seems to be caused by BP spike especially from sitting to standing. I only seem to have this issue when exercising regularly when my Resting HR has decreased fairly significantly.