50 minute run

50 minute tempo run today was brutal.  My heart rate was out of control. I did 15 warm up, 20 tempo (HR 2-3), 15 cool down.  Within 1 minute of my warm up my heart rate was already into zone 2. During the 20 minute tempo portion my heart rate was shooting way over my LT rate and I was only doing 8:20 pace. It was crazy.  So my final was 9:00 minute pace and 160 bpm.