Ran a 16 mile long run a few weeks ago. Afterwards, I felt fine until 10 minutes post run, I started to get what I guess was tunnel vision on my post run walk. Tried not to panic and went into deli and grabbed a water and apple and chugged the water. Went back outside and felt dizzy again - feeling subsided about 3 min later.
Went to doc for blood tests and everything was normal, no anemia or concerning results. No heart issues.
I’ve run a few marathons and this never happened before. I drank 2 gatorades and 3 gels during run. Run started out with warm weather but last hour the weather was humid, sunny, 80 degrees - mostly uncomfortable
Doctor didn’t seem concerned and gave no reasoning or explanation for the dizziness.
Any insight? Perhaps dehydration mixed with heat and humidity but I’ve run in worse temps with less hydration before