Two in a row...

Two quicker miles in a row tonight after a 10 min/mile warm up with Chief.  Tonight's run was also the second in a row that I ran slower than expected.  I don't know if it was the high humidity and 79 degree temperature or if I'm over training.  7 min/mile pace has been easy for me to get to and hold, it's easy hard anyway.  Tonight I ran a 7:20 mile followed by an 8:40 mile for 16:00 total.  I held a 188 bmp average which is 88% of my max.  I should have run the two miles in 14 minutes at that level of effort based on the last month of runs.  I felt like I was running around 80% as far as breathing and never felt winded, just very hot.

Stats:

10 min mile warmup, 75% HR

2 miles in 16 mins, 88% HR

Perplexed at drop in performance