First Speed Workout on the Track

Friday I wanted to run but had limited time and the temperature was 0.  As in ZERO.  Like no degrees at all.  I decided that this might be a little too cold for what I felt like that day so I was going to run on the track at our Y. 

The thought of counting out 40 laps on this track for 5 miles was just overwhelming--I just knew I would lose track around 23 and then not know where I was.  So I googled track workouts and found this one:

10 x 400 with 400 rest intervals

I went ahead and assumed one lap around our track was 200 since 8 laps was a mile.  (That's kinda correct, right?)  So two laps would equal the 400 that the workout was calling for.  I did the math for what time I should shoot for based loosely on my average 5K time.  The directions were to find your 5K pace, divide by 4 and subtract 10 seconds.  Basing on 26:00 for 5K, I came up with 1:56 for my time to complete the 400.  I have run faster 5K's than 26, but haven't run one in almost a year so I thought I wouldn't make my goals too lofty.  So this is what actually happened:

1:45
1:46
1:44
1:46
1:48
1:45
1:49
1:52
1:50
1:45

When I saw what my first lap was and I wasn't full out sprinting (which I wouldn't be able to maintain x's 10), I knew I could keep that pace.  It was faster running than I do for a regular run, but not sprinting. 

I have no idea if this is fast, slow or otherwise.  I wonder what my 5K time should be based on this workout...  I cannot be bothered to work to the math backward.

Pros to indoor track workout:
~not cold
~went by fast--keeping track of splits and rest laps kept my mind occupied
~I wasn't bored so I didn't need music
~5 miles in 40 minutes--not too shabby!

Cons:
~weaving around the walkers
~needing to clear my nose and not being able to...
~high fiving the mentally challenged adult EVERY time I passed him.  I was down with it the first few times, but after about 20 laps, I was over it.

I do think our track is based on yards and not meters and this workout was in meters...  does that matter?  Did I still do 5 miles?  Gah.  This math is killing my head.  I should ask a 5th grader.

Do you do track/speed workouts?  Do you like them?

Is this fast or slow or average?  I really have no idea.