Two degrees of separation

Run Type: Steady 14-km at HR of 145-155 bpm.
Route: From home to Komazawa park, three laps and return.

Crikey! It is amazing what a difference a small drop in temperature can make.

First of all, let's go back two days to Wednesday night. it was warm and steamy, probably 28 degrees, I was running at a heart rate of around 150 to 155. Found it hard to keep to that level as it would climb to 160 as soon as I forced the pace and on uphills. The pace at this level of exertion was around 4:37 to 4:40/km.

Now, on this run this morning there was light drizzle and the temperature was 26 degrees according to Weather.com. This time I found it hard to get my heart rate up to 150 until well into the run--if I wasn't careful it would easily slip down to 145. What's more, the pace was 10 seconds per k faster on the uphills (4:28) and 20 seconds faster on the downhills (4:15 to 4:18) than on Wednesday. Ran from the park to home in 0:17:26, an average of 4:35/km. Heart rate was mostly at 150 but finished at 157.

A pretty good benchmark run.