> Or when you are working at high heart rate close to your maximum. When I was in college, running on the track, I decided to see how fast I could run by ignor

> Or when you are working at high heart rate close to your maximum. When I was in college, running on the track, I decided to see how fast I could run by ignoring the stress and pain. My vision began rolling and surging in a weird way impossible to describe. I stopped and laid down on the ground, unable to do anything but pant. I realized that what I had done was extremely stupid and never did it again.