1-month vertigo following heat exhaustion

I'm a 37-year old male in excellent physical condition, swam in college and have been competing in triathlons for 15 years.  Exactly 1 month ago I went for a 2-hour 35 mile bicycle ride in the blazing Florida summer heat (I know, not the smartest move)  Though I've trained in the heat before and brought fluids with me on the ride, the 100+ heat index took it's toll.  I ended up with extremely severe heat exhaustion toward the end of the ride, I probably should have went to the ER following my return home.

Upon awaking the next day I had a severe, crushing headache with pressure.  Four weeks after this incident I have sensations of vertigo when moving my head side to side, up or down, or bouncing my head such as when I run.....it's as if my eyes can't follow along with my head.  Standing up after I've been sitting also creates this vertigo effect.  The vertigo also creates an unsteadiness to my balance. I've also noticed a feeling of pressure in the upper, inside corners of both my eyes and discomfort moving my eyes from side to side.  This vertigo has all but put a hold on my exercise as any head movement triggers the sensation.

Also of note, I assume as a side effect of the extreme heat exhaustion, I appear to have become heat intolerant.  Any exposure to stagnant heat, even without exercise, and my heart rate shoots the roof along with associated dizziness.  During these episodes I just can't get my heart rate to come down and must quickly get into an air condtioned building.  Almost called 911 as one time I nearly fainted.

Being I've never felt any of these symptoms before I fear the severe heat exhaustion/exertion has caused all this.  I went to a neurologist 3 weeks ago for a physical exam and MRI of the brain and all came back OK.  Neurologist just told me to "rest."  My GP did blood work and all came back normal, blood pressure was normal, he recommended I see an ENT Specialist.

Could this be something vascular that occured in the brain that wasn't picked up on the MRI?  Could severe dehydration & heat exhaustion trigger these symptoms?  Could the vertigo be due to a sinus infection or inner ear issue?  I'm concerned as I've never experienced vertigo like this before and never had a month-long headache before.  Thanks for any advice!

[danno61]

Perhaps the heat is triggering BPPV. I'm being tested for BPPV today and have noticed that I only get it in the summer months of June and July (which is when the temps in AZ are consistently above 100 degrees). If you are getting the vertigo based on the position of your head, an ENT mayschedule an ENG to test for BPPV. By now your vertigo may have gone away as mine does for the remainder of the year.