This might be a stupid question, but why do I feel so much more tired after running 2 or 4 miles as opposed to 6 miles? After my 6 mile runs, I don't feel out of breath or tired... I feel wide awake and great! But after my 2 or 4 mile runs, I feel exhausted. I'm running them at the same pace, I think. And at around mile 5.5, I even start sprinting the last half mile. Maybe it's because it takes me awhile to find my own "pace?" Just looking for some input.
If you haven't been running much, it may indeed take a while to find your pace. I've found that it takes me about 2 miles to warm up and get all the kinks out. Miles 3 and 4 are mush more comfortable than miles 1 and 2.
maybe it takes a bit longer to get that runners high, endorphin release as it were, than at lower milage, endorphins are triggored by extreme stress, and 4 miles is not stressful or painful enough to get that release. something to think about.