Tempo, long rest, tempo

I’ve measured my heart rate at 200 during a tempo workout (after a 200m run and a total of 2400m of runs). It was a tough workout, but I didn’t feel any muscular fatigue. The workout was 5x(run 100m, walk 50m, run 100, walk 50, run 200 walk 100, run 100 walk 100). The 100s were in done 15.5.16s and the 200s in about 32-33s. I’m a 11.01/22.4 sprinter. Has anyone else measured their heart rate during tempo workouts? Was mine unusually (too) high?