30:00 flat progression run + 4 x 1:00 surges intervals 54:19  10.01 km (5:26 / km)
Totally failed the run, but still glad I was able to do it till the end.
Okay, here are my mistakes:
1. First I was going to run in the morning (indoor track), but when I woke up I still had some pain in my stomach, so I decided to run after work. So when I came there was a HUGE amount of people on 200m track and it was really more of a slalom than classic running.
2. My stomach was much better, but still not ideal and that affected my pace greatly.
3. I ate 1.5 hours before training and that was a mistake, I still had a full stomach.
So, I started running at easy pace planning to fasten every 5 minutes. But it seems that the watch shows pace indoors quite inaccurate. It uses step counts instead of gps, by feeling I was running something like 5:10 but it showed 5:40 instead, so I had to run faster. After 5 minutes the plan was to increase pace to 5:00, so I started to run '5:00' according to the watch, but that felt really hard. 5 minutes later I increased to 4:45 and that was the end (the plan was to come all the way to 4:10, which I usually run at 165-170 bpm). After 5 minutes of running at that pace (with 170 bpm, which is higher than my lactate threshold!) I was completely exhausted, had to stop for couple of minutes to catch my breath and them ran the rest at 5:00, just couldn't run any harder anymore. After that was 10 minutes easy but even at really easy pace I had 150 bpm heart rate. Then came 4 intervals with paces 3:46, 3:38, 3:57, 3:25. Between them I was walking, not running, and even walking I could get my pulse lower than 140.
I think the first reason was that I started too fast relying on the watch and that affected the whole run. The second possible reason probably is that I got used to running on outdoor track where temperature is cool and no other runners rather than me. Here it was pretty hot and I always have problems running at warm temperatures (no habit). After workout my legs didn't feel fatigued at all.
On one hand I'm disappointed, on the other hand I understand that I wasn't feeling very well and next time I could do better. And probably next time I need to run by heart rate, not by pace?