[Update: the laps are all run with no rest between, and the HR is averaged over each lap, I do a 2 mile warmup run at a slow pace and a 2 mile warm down after]
Next, I wrote some software to read in my Garmin data and do a best fit line to it.. turns out that running pace vs heart rate is very linear (unless you running paces very very close to your max HR).
Below you can see this data from March 7th. The 'slope' is the beats/per/minute/per/min/mile. i.e. to speed up one minute per mile, I need to run with a heart rate that is 11.82 beats/min faster.
The table that follows then shows this data for each 1/2 min/mile pace that I might attempt to run. It also shows the percent of my 'working heart rate' that each pace is. My resting HR is 48 beats/min and my max HR is 168 (measured on treadmill at Dr's office) so I have a 120 beat/min WHR.
The cool thing about this technology is that you can actually measure your improvement WITHOUT RACING. You don't even have to run fast on the track (I do just for completeness and better fitting of the data), you can run at a bunch of slow paces (say 12 to 10 minute miles) and then week by week
see your improvement.
I plan to do a calibration run every few weeks during my current mileage buildup...stay tuned to see if I get any improvements!
Slope -11.82, Intercept 231.26, weight 170.6 lbs, temp 60 F, no wind