My wife and I were running a few weeks ago, and toward the end of the run I thought I may have hit a runner's high because my legs felt a lot lighter, and I had this weird feeling. Turns out it was just REALLY low blood sugar . I've been type 1 diabetic since I was 7, and when we got back to our car, I checked my blood sugar. It's supposed to be 80-120. Mine was 45 .