Well, I wasn't able to maintain the 175 beats for the full 20 minutes as I was sure I wouldn't. I actually felt very pukey trying. I did get up there and maitain a pretty good rate though. Breathing was heavy, bike was soaked and I cursed my trainer in my mind for the last 40 minutes.

The stats:

Riding time: 1:00

Average heart rate: 161 bpm

Maximum heart rate: 177 bpm

Calories burned: 800

Distance: 20 miles