So for my fellow high altitude residents that have raced IM at lower elevations (specifically Arizona), did you notice any major difference/advantage moving down in elevation? And if you did, what were these changes?
I've run a half-mary at Arizona and was able to run a bit faster but was not racing by heart rate, as I will for IM. So my big question is how much faster were you running/riding in Zone 2 at lower altitude?
I used to live and race in Houston and I had done the northern portion of the IMTX route a bunch. Most of the time, it was pretty (to very) challenging. I signed up for IMTX 2011 while living there and then I moved to Denver 5 months before the race, so all my training was done here. The altitude and more challenging terrain are DEFINITELY and advantage. I did the Galveston 70.3 before IMTX and it was much easier to keep my hr down. I did a test ride on the IM course with my old riding partner, and I was much faster than her. My experience during the IM was that it was much easier to keep my HR down (I wasn't going for speed, this was my first one). I don't think my HR went above 155 on the bike and the swim felt pretty effortless. What was hard for me was the lack of heat training, since it snowed right up to race day. I just wasn't heat acclimated. But you shouldn't have that issue for IMAZ.
Todd, when i did Redman I was going from traing at altitude to just above 1,000 feet above sea level. I've also run a couple marathons and half marathons at lower elevation. Definately there is an advantage and you will most likely be somewhat faster. However, I would not bank on being X percent faster at the same heart rate becuase you are at a lower elevation. For one thing, my HR threshold seems to be higher at sea level. I know a lot of people will disagree with this but I've tested myself at sea level and my threshold is about 5 BPM higher than at mile high. Similar to when I run or ride above 10,000 feet...I can't get my HR as high as when at mile high. I don't know the science behind it...this is just my experience.
Anyway, I believe this is your first 140.6? It's going to me a new experience for you physically and mentally. While racing with the HR monitor I think is a good idea I wouldn't put too much emphasis on trying to estimate how much faster you might be at the lower altitude. Learn to listen to your body and let it guide you through the race...especially on the bike. Alot can happen in 10, 12, 14+ hours...most likely something is going to happen that you were not counting on. It did for me...over an hour delay, rain, cyclometer died, etc. Just stick with your training plan and excute on race day. Yes, the lower elevation is going to help you...but not so much that it should really make that much of a difference in you goal estimates for each leg.
Thanks for the info! I'm more curious than anything. This being my first IM, I have very loose goals and am looking to "enjoy" the experience as best I can. More than anything, I just don't want to be overly concerned when I'm riding/running in Z2 but seeing a faster pace or speed than I'm accustomed to.
I live/train in Colo Springs and did IMAZ in fall of 2008.
I went sans HRM and even pulled the sensor for speed from my rear wheel and went on Perceived Exertion and Cadence alone during the bike.
Spinning in my usual ranges on the flats and hills did reveal a clear reduction in perceived exertion, and I chose not to push it, but to just soak it up. You can check my race report for specifics, but I felt great pretty much the whole event minus maybe 5mins total.
I've seen studies both pro and con on Training at, or Sleeping at Altitude or Simulated Altitude. A couple of these include %s. Draw your own conclusions, but for sure it was a noticeable benefit to me.