Bike TT, HR Results again

I posted this a while back, and want to give pose this question once more. My 30" TT have been on the same course, conditions pretty similar (temp, wind, etc.). I do not have any power data, just HR, cadence, distance. Complete? No, but close enough. Just having a difficult time decoding this stuff and looking for some help.

For some reason, my AHR for the most recent TT is lower, even though the distance covered was similar. Yesterday, nutrition was slightly different (had CLIF Electrolyte with caffeine) that previous (Gatorade Endurance). Cadence was also lower, but that wasn’t really planned. I could not have gone any faster (I don’t think). I was breathing heavily the whole time. It was overcast yesterday AM, but far from cool.

Thanks, and sorry for the long data listing…

7/25/09
0-10’
3.61 miles
152 AHR
159 MHR
98.6 Ave. Cadence
21.6 mph

10’-30’
7.66 miles
163 AHR
167 MHR
99.4 Ave. Cadence
23 mph

8/15/09
0-10’ (actually 10.18)
3.89 miles
143 AHR
154 MHR
96.8 Ave. Cadence
22.7 mph

10’-30’
7.83 miles
162 AHR
169 MHR
95.7 Ave. Cadence
23.5 mph

9/7/09
0-10’
3.97 miles
147 AHR
154 MHR
91.1 Ave. Cadence
23.8 mph

10’-30’
7.82 miles
156 AHR
162 MHR
90.8 Ave. Cadence
23.4 mph

Do you know what your Anaerobic Threshold (AT) or Lactate Threshold (LT) is? Without that, the variations are just that, variations. Judging by the heart rate at the 10" mark vs later, you weren’t warmed up enough or didn’t ramp up quite enough. You should be able to get to your AT in 5-6 minutes in a TT of this length.