Dizzy during and after workout - Medical experts?

Sarge516

You can see my story here for some back ground:
http://www.myfitnesspal.com/topics/show/720595-minus-89-lbs-w-pics

Looking for some info from the experts.

I get dizzy when working out hard, and dizzy after workouts, even when my HR has come back to normal. I'm in pretty good shape now, resting HR is mid 40s consistently, BP is normal. I wear a HRM when I workout, and my max HR has been high 180s a number of times, and I don't get dizzy then. I can get dizzy when my HR is in the 140-160 range. I train HARD and give it a lot of effort when working out. Not trying to kill myself levels, but I'm not slacking either. I might be hypoglycemic a little - never diagnosed, but I get weak and shaky when I haven't eaten.

Here's an example that happened 10 min ago and prompted me to post this. Working out doing HIIT training. Doing 3 min sets rotating between 3 stations. Doing plyo exercises, some kettlebell, some push ups, that kind of stuff. 3 min on, 1 min off for 55 or 60 min. My HR is 140-160 throughout. I'm 39 years old, and used to weigh 285 lbs, now I'm 195ish. I got one or two dizzy spells during the HIIT, and one once back at my desk.

I ate 4 slices of turkey bacon and 2 eggs for breakfast at 6:00am, had an apple around 8:30 am, a protein bar at about 11:00 am along with about a cup and a half of berries with low calorie vanilla yogurt on top for a snack. I drank about 2L (64 oz) of water over the course of the morning. Workout began at 11:30am and went until 1:00pm. I did 30 min of weight training first before HIIT. Come back to my desk, have a scoup of protein powder and water, and I get a dizzy spell. So much so that I have to drop my head between my knees at my desk (that goodness I have my own office :]) as I fear I might topple over in my chair.

I feel it is blood sugar/glycogen related, and not cardiovascular related based on when it happens.

Opinions? This happen to anyone else?