Treadmill runs

I read a bunch of other blogs and people always post these really interesting speed workouts they do on the treadmill.  In my mind I keep thinking it'd be great for me to do, but in my mind I'm also intimidated by running at speed for a while.  So I picked a speed roughly equal to my most recent 5K speed.   My brain was still intimidated but I tried it anyways.

Warmup - 10 mins
Run - 1 min, 2 min, 3 min, 4 min, 5 min, 4, min, 3 min, 2 min, 1 min at just faster than 5K pace with 2 mins slow jog in between each. 
Cooldown - 10 mins

Actual: I didn't make it the full 10 mins because my stomach got upset, but otherwise it went okay.  Sometimes it's fun to run faster than I normally go.  Not sure if this was a real confidence booster or an aberration, but it was fun.

Heartrate: Obviously I didn't care about my heart rate during the fast parts.  I wish my heart rate would've come down a bit more in the between times.  Recovery is always important.