A very silver lining

I tried a tempo run last night. I say 'tried' because I was tired and couldn't keep my heart rate up. I'd aimed for faster than 7:40 for each of 3 of my usual time-trial 1.5-mile laps. The best I managed was to get the second lap up to 7:42, but my pace and heart rate fell for the last lap.

But...

That second lap wasn't even at marathon heart rate, and yet I was running 7:42 pace. Could my 3:30 target for the marathon actually be rather conservative? It will be interesting how things go in 2 weeks time at the Mad March Hare 20, where I'll try to run the last 15 miles at marathon pace.

1.5-mile continuous laps. 3 mile warm up not included

Lap	Lap time	Mins/mile	bpm	%of max HR
1	11:46	7:51	136	79%
2	11:33	7:42	142	82%
3	11:48	7:52	141	82%