HIM Run pace - real world edition
I've raced 2 70.3's over the past handfull of months in relatively similar conditions. Austin last October and Galveston a week or so ago. In both cases I biked around .75IF. For both races my VDot target pace was to go out at 9min/mi and speed up to Z2 which is 8:30 per mi.
In both cases I could not hold the 9min mi pace and slowed. 9:40 avg pace in Austin and 9:43 in Galveston. FWIW I had a 10:20 pace IM run in Coz in between them.
I will be racing another 70.3 in about 2 months and am thinking that regardless of how great I feel in training that I should take the first 3mi at a 9:40 pace and go from there. I dont think it is nutrition related. It might very well be heat related. But the next race will be hot also. Worst case, going out at 9:40 will prove too easy as I cross the finish line but thus far that hasnt been a problem 
.
Thoughts?
Comments
my standard plug for using HR and RPE to pace your run when the air temp gets above about 25C (78-80F). During training, you should get very good at knowing both what it *feels* like and what your HR is at your chosen race pace, in this case (HIM), MP. Lock those into your neuro-muscular memory, and pull it out on race day.
Nominal temps are 50-60F. Most well trained EN athletes can handle using their VDOT directed pace on race day for temps up to 20F above that range, with some prudence as the temps and sun intensity get higher. But once you get near 30C, which is about skin temp, then it becomes progressively more difficult to offload internal body heat, and you MUST slow down, either your run pace, or by walking, to avoid heat exhaustion.