This could be nothing. It could just be "me." I do have a history of low blood pressure and dizzy spells every few years (not constantly or with any predictable regularity) that leave me susceptible to gravity. But I've never had it happen after a run before. I also have a history of heart palpitations for 30 years that I know are brought on by changes in pressure, i.e. getting up and down to talk to small children close to the ground in a sudden motion, or sound waves in the movie theater. We all have our problems. True, this was the longest run by time and distance in almost a year. It certainly wasn't in the warmest conditions. And I wasn't pushing my pace. I was running my comfortable pace and only aiming to increase my time by 10%, which I did. I should also add that I was drinking my slightly salted lemonade mix, which I drink all the time. I drank both bottles of it gradually over the course of the run, never feeling more than mild thirst. This is just a little more than what I have been drinking on my other "long" runs, which this was a little longer than, so it all looks right percentage wise. It wasn't particularly warm, just around 60°F when I started and 69°F when I got back to the car. It was a bit humid for Idaho, with the sun shining, but weird occasional little rain drops. I got a few on my sunglasses, so could verify that's what it was. I wasn't pushing my pace or sprinting in any way for the last lap, which I have done before for fun. Maybe I need to run faster at the end to raise my bp??!! When I slowed to a walk, I felt something on the bottom of my foot, so bent down to brush it away. Then, after a few more steps, I suddenly felt quite dizzy and sunk immediately to a squat, hoping I wasn't going to pass out on the path. There were plenty of people fishing and walking the pond loop, but no one right where I was or that I could see at the moment. It was kind of a concerning moment. Of course, I was also thinking it would be very bad PR for barefoot running... In a few seconds (I wasn't watching my watch), I felt up to trying to stand and made it back to the car at a slow, comfortable walk, but am still just a touch light headed. I have eaten lunch now, and drunk more water. Will probably make more lemonade, too, but drink it "full strength." Ha. So, that's my story.