Not a workout I guess but entered a race on Rouvy last night. It was brutal. I’ve done a bit of racing on Zwift before but Rouvy doesn’t group riders at all they all go out together it seems.
I got to the front but was quickly dropped by 15 or so, within 5 minutes. Then stuck with a group of about 5 for over 30mins. At the 40 minute mark I had to let them go and recover for a bit before digging in again to keep in the top 25 (from about 150).
My heart rate was 186bpm for 39minutes 
with a max of 201 where I tried to bridge from the group I was in to the next bunch. Caught them only for the rest of my group to keep going and drop me.