5k Running program zones/speeds question

I started the 5k running program and did my first “hard workout” … well I almost died. It was a 10x hills at 6-8% incline for 0.25 of a mile (at 8.6mph) and rest for 0.25 of a mile at (7.3mph)… needles to say I was sucking!
I was wondering how Zwift calculated my required speed/zones. I haven’t done any sort of LT test on the treadmill or anything for that matter. I would like to tweak it to something realistic for next workout.

As a reference. I am using a NordiTrack Commercial 2450 with a Strydr Pod, Wahoo HR monitor on a Samsung S5e tablet.

Thanks for the help

@Jose_Centeno - I am fairly new to (Zwift) running. From what I experienced, it took my fastest times I’ve done on Zwift as a benchmark.

I have seen that you can go in and edit that. From memory: if you are in the workout selection screens, it shows the workout on the right of the screen and this includes the “benchmark” times. There is an option to edit above this.

That is correct, it’s based on your best times. You can alter them. Also when in a workout you can change the difficulty + or -

That being said given your experience I’d say you’ve had an ideal workout that’s pushed you hard