Last night I had my worst interval training *EVER*. I warmed up for 2 miles, and then I wanted to do sub-4 minute 1000 meters. I was actually aiming for 3:55 - two weeks ago I did 7x600 at that pace, and though it was hard, I could do it. Yesterday, the first was OK, I ran 3:54, but in the second lap of the second interval, I just lost it. The strength left my legs, and my heart couldn't keep up. I slowed down to the last 200 meters so much that I finished with 4:04. I almost decided to go home, but then I changed my mind and decided to finish the workout. I had to give up on the pace and I just ran the 1000s by feel around my VO2 max. I am ashamed to admit that the last three intervals were ~4:15 each. That was the best I could do.

I have no idea what caused the problem. Maybe I'm not ready, or just don't have the physical capabilities to go under 20 minutes. I have had a lot of stress at work and in private life lately, but this had never influenced my running before. I also was so busy yesterday at work that I barely drank anything until 3pm, but then I started to hydrate like crazy, and I only ran at 10pm.