I ran a 5k time trial / anaerobic threshold test this weekend (http://tpks.ws/N37XYX7VDJDAFTI4FEYTRMETSU) and averaged 183 bpm heart rate over 30 minutes. This was all out effort in heat/humidity, ~23 minutes shooting for 5k PR and ~7 minutes trying to maintain that intensity to get a full 30 minutes.
If the pacing were to vary, it’d be ideal for the last 20′ to be faster than the first ten. However, HR didn’t fall, so the pacing is probably close enough. The average was 183 over the 30′ and 187 over the last 20′. I think you can use 185 as AnT HR.
I’m wondering if it’s possible my AeT is really around 150/160, and by starting the drift test too low it skewed results. Should I try again and shoot for the 150/155 range? Or should I just take this as a sign of my aerobic deficiency and train at 140 bpm or less, walking as necessary?
Starting a drift test too low shouldn’t skew the results. If the load is lower, the drift should be lower. It sounds like you have ADS and your AeT HR is lower than 140. The Pa:HR over the test portion (from 15′ to 1h15′) was just under 10%.
Your half-marathon effort will have less drift because it’s closer to AnT. The difference between the two thresholds is:
* AeT HR could drift but doesn’t.
* AnT HR doesn’t drift because it can’t.