5K fartlek on treadmill

This morning was an exercise in frustration. It started off well enough. I looked outside and it was 29F (-2C) and clear, and the roads looked mostly empty of snow (it snowed quite a bit yesterday and was supposed to snow a little more last night). So I got all dressed to walk outside, with all the layers and gloves and hat and pepper spray and headlamp and rear blinkie and reflective vest. Then I walked out my door onto the driveway by the side of my house. It was coated in ice. Uh-oh. I walked out to the street and it was only slightly better. Goody, goody. Black ice (which is just ice on the road which is hard to see). Walking outside was not going to happen. So I thought I'd go to the indoor track. Uh, nope. It's a holiday here (President's Day - for my international friends, this is to honor our presidents Washington and Lincoln) and so the indoor track isn't open until 9 am. That wasn't an option. So that left one thing: the dreadmill. Unfortunately, those darned things are just not really accurate, so I knew I wouldn't be able to gauge my fitness level very well, but I would be able to get a good hard workout. And that I did.

I warmed up with 1 mile in 10:36, doing a few pick-ups and taking it easy in between. I stretched out a bit and got started. I have had to adjust my times a bit from what is on my watch because I waited until the 'mill was almost up to speed (6.6mph for my fast intervals today except for the 4th one, which was half at 6.6 mph and half at 6.5 mph) to push start. My watch says 5:32 but it was really 5:39 for the first km. Then 3:06 recovery, and 2:49 fast 500m. Then 3:15 recovery (I was really feeling it and my HR was quite high), and 2:49 fast. Then 3:15 recovery and 2:50 fast. Then the wheels fell off a bit - I slowed down a lot on the recovery AND had some serious math issues. 500m is 0.31 miles, and the $#*(& treadmills only have miles because Americans are too colossally stupid to actually go metric and get with the program like the rest of the world. Anyway, I had to add 0.31 to 2.48 and somehow had it fixated in my head that it was 2.86 (probably because 1.86 miles is 3km...), so my 4th recovery was actually 0.38 miles (544m). Oops. Even more oops, it was in 4:06, which when translated to 500m instead of 544 is a ridiculously slow 3:46. I am wondering if this can be right? But that's what the watch says...and my HR was an ave of 173 (!). Ouch. Finally, the last 500m was 2:45 (it was at 2:49 pace like the other so not sure what is going on here).

So, my total was 30:14 if you count the first km as 5:39. Hmmm, that is kind of slow for the effort. Like I said, I don't trust the treadmill accuracy very much. And I'm not sure where the 3:46 came from. I have no idea what all this means, except that I had a very good and very hard workout. I was really pushing it, and my ave HR was 170 for the whole workout, which is crazy high. I feel pretty good now, though, and nothing hurts.

Garmin connect data here.