Training & Nutrition - Lactate threshold... am I doing this right?

Did I work hard enough? I'm trying to roughly figure out my lactate threshold (or functional power threshold?), based on heart rate, so that I can use that as a guide for training and race efforts. I did the test described here, on a trainer:
http://www.bikeforums.net/showthread.php?43102-2x20-Anaerobic-threshold-test

It's 2x20 minute efforts at a heart rate you can sustain for both intervals.

I thought I was suffering, and I didn't know if I could hold it... I wanted to quit, my legs were noticeably burning about 5 minutes into the intervals, buckets of sweat, my cadence was around 95 and my heart rate averaged 180 (started around 175, drifted up to 185, same cadence and gearing maintained throughout, though). After I stopped, I felt pleased with my effort, and didn't think I could have tried much harder.

However, my breathing was steady (I could say a few words or take a drink), I never felt nauseous, my legs are not at all stiff today, and don't even feel weak.

So, was I trying hard enough? Was I even close? How should you feel when doing a test like this?

Yes. At high cadence, necessary for these intervals, your legs won't be stressed enough to get sore if you are in good condition. The lactate is gone in an hour. Pleased with your effort is exactly how you should feel after. During, you should be breathing deeply and relatively fast, but not panting at all. Saying a few words is perfect. If you can hold the gear during the interval, and use the same gear in both, that's evidence of good aerobic conditioning. Ready to go.

Cool... good to know I'm in the ball park with that effort (despite feeling suprisingly just fine today, I'm really not sure I could have worked much harder). I'm in good shape, but this will be my first year giving racing a try, so this testing my limits concept is pretty new to me.