Bike Time Trial -- BIG improvements!!

This morning I reluctantly got out of bed and drove down to River Rd (great to bike on - nice bike lane, low traffic, no stops) to do my Time Trial. It's been a little while since I've done a time trial, mostly because I was so focused on what to do about my running injuries. Now however, I am organized again, and I thought it was time to check my heart rate (HR) zones.

First I'll give you some background info on what I was doing. The test is called a Lactate Threshold (LT) Test. This involves pushing yourself as hard as you possibly can, to the point where the body is unable to take up enough oxygen for energy and produces more lactic acid in the bloodstream than the body can clear. Lactic acid is the limiter of athletic performance, when your body can't clear it you slow down to compensate. (Its that awful burning feeling in your muscles, that you feel when you are pushing yourself really hard.) So, the key to enhancing athletic performance is to raise the HR at which you produce lactic acid, and increase your body's efficiency at getting rid of it. Basically, what I want is to push my LT as close to my maximum HR as I can, because that would mean I could exercise at a very high heart rate before I produce lactate. (meaning= I can go really fast for really long!)
There are a bunch of tests available to find out what your LT HR is, I chose the 6mi time trial because its free, and I can do it without an assistant. You basically find a course with no stops and ride as hard as you can for the 6mi with a HR monitor. Your average HR for the test is your LT. So, here's what I did:

15min warm up, which included 4x20sec high intensity intervals, to get my legs ready for what was coming. Then I rested for a couple minutes. When I was ready, I started from standing, set my watch and started riding as hard and as fast as I could 3miles out, turned around (watching for traffic) and 3miles back. When I was finished I hit the lap button on my watch and cooled down for 12min until my HR was all the way back down to 125.

I did this at 7am to try to beat the wind, so that my test would be accurate. I did feel a little wind but it wasn't anything much, and the course I chose wasn't perfectly flat, but its the best I can get. To keep things constant I will always do this test under as close to the same conditions as I can.

The last time I tried to check my LT I did it on an indoor trainer because it was winter (and I'm a baby about the cold). I did a different type of test where you ride for 2 segments of 8min, anyways my LT HR was 167. Today my Avg HR for the ride was 172!! I pushed so hard, I was really happy about that. I was surprised too because I haven't been doing a lot of threshold training, so just wait until I am!

Here are my full results:
Dist- 6mi
Time- 17:04.43
Avg speed- 21.1mph
Max speed- 23.7mph
Avg cadence- 93rpm

Avg HR- 172 *New Lactate Threshold*
Max HR- 180

Weather:
temp- 73F
wind- NE 3mph