IM Marathon goal pace

Don't worry so much about running pace as much as pacing by your HR. You sound like  you have a pretty good grasp on how the whole HR thing works.

I am running at a HR of 160 or below on Sunday for IMLOU. With the forecasted heat and humidity I am guessing anywhere from 8-8:30/miles, however if it turns out to be 9min/miles then so be it. I know that if I go over 160 for an extended length of time then I will end up walking.

You are training well and training smart you will be fine for IMFL in November (it should be much cooler for you than us!)

My coach has me focusing primarily on my HR because on race day my actual pace could be faster or slower depending on conditions.  If I were to try for a 10:30/mi pace on a really hot day, I'd blow up before the 10k mark.  Likewise, if its cool out I could probably go faster.  Its all about metering out the energy throughout the day using my HR as the control point.

Honestly, my goal pace is anything less than crawling. 

Looking at your running paces and races, I think 3:45 is very aggressive.  If your long run pace is 9:30, that's probably a good place to start out at.  After a few miles, re-evaluate given the feedback from HR & RPE.  If HR is too high, slow down.  If HR seems too low given RPE, slow down and get some fluids/fuel.  If HR seems low and RPE seems easy, take the pace up a bit.  Re-evaluate again in a few miles.

A great thought to keep in mind throughout the day is that the race doesn't start until mile 18 of the run.  Once you get to mile 18 of the run...just don't slow down!

I would have to chime in and say to use RPE over HR. Heart rate isn't always a good indicator for exertion. In my case, most of my long runs that my RPE is 13 or 14 which I would consider marathon pace give me a HR of around 130 or 140. When I did my first and only marathon I started off at an RPE of 10 or 11 and my HR was 160! I backed off to get the HR down and realized I was at 9:30 miles. I decided to just use RPE and get it up to the 13 or 14 range and held my HR in the 160's for the entire race.

Biking is even a bigger difference. If I to a hard 90 min ride in training my AHR might be 145, in a race I'll avg up to 175. Racing for me elevates my HR just from the atmosphere and nerves of the race. If I went by HR, I might be walking the marathon.

My coach takes his HRM off during IM races and used RPE as a guide.

Just my $.02

Bob

BTW - I'm doing my first IM in 17 days and 12 hrs, so take my comments with a grain of salt!  

I see your point Bryan. I train exclusively using HR as a guide as well. I have had LT tests, VO2 Max tests, blood lactate tests and my coach has set my HR zones according to those tests as well as some max effort track tests too. Even on these tests I cannot get my HR nearly as high as during a race.

I do feel that everyone should train using HR as a guide, it's a great tool. RPE is a good "back up" during training. Race day is a different animal. If a person's HR is elevated for whatever reason and his/her RPE is really low are you saying he/she should back off their effort to lower the HR?

This all being said I just looked at my HIM run results and my AHR was 156, the same as my marathon AHR. Right in the middle of Z-2. I guess the HR zones he set up for me are correct. It's the races under 15K that my HR is elevated.

Oh great! One more thing to wonder about before the IM in 2 1/2 weeks!! Have I trained right this whole year. Thanks Bryan!!  

As someone who ran the entire marathon leg(that's right, ran the entire marathon leg with no walking even at the aid stations) at IMLP, my first Ironman, your long run pace (which should feel pretty comfortable) is a good goal to try to hold.  I started off at a pace that felt "easy" and focused on trying to basically keep that pace as best as possible.  I felt great almost the entire time (except a brief time early on which I fixed with more calories) and felt better the last half them I had ever felt at that point in earlier marathons.  Now my marathon time was pretty slow- 6 hours (around the same pace as many of my long runs leading up to the race), but I was in better shape throughout the marathon than probably 90% of the field from what I saw and heard.

Just remember that what feels "easy" and "comfortable" at mile 1 is likely not to be the case at mile 18.  If you can focus on trying not to slow down (the real key to an IM marathon), you will have a much better marathon then most.  And the mile 18 goal is a good start.

Actually yes a no… training and racing by RPE is probably the best way to go but in order to get in tune with your body requires experience and lots of training hours. The more I train the less I use my HRM and I stop using it altogether for racing this season.

I would say that RPE most of the time (except in the 1^st portion of a long race) will be a better pacing indicator than HR by far because HR responses might have nothing to do with what’s going on. Your HR can be affected by so many things it would be crazy to solely rely on it. If you are having the race of your life, yeah everything will be peachy but if the day is extremely hot, if your nutrition is not working or you are just getting tired from the race your HR will act on you. The take home message is to not rely on only one thing if you have other tools. Use it all to enhance your training not to dictate/limit it…

You've already been given advice on using HR.  I think that's the way to go.  But, also you need to figure out how you are going to get to your marathon goal time.  How to get there starts on the bike.  Too hard on the bike and the run suffers.  For IMFL last year I rode a conservative bike and stuck to my race plan even when people were flying past me.  On the marathon, I used a run/walk routine.  A lot of people will 'pooh-pooh' run/walk, but I'm here to tell you it works.  I planned to run a 10:30 pace and had a goal time for the marathon.  This pace was based on my only other marathon.  I set my watch's timer to go off at 4'30".  I ran 4' then walked 30".  I planned to hold this routine until mile 18 then evaluate how I was feeling.  At mile 18 I would decide to continue run/walk or just run straight through to the finish.  At 18 I felt great and ran straight through passing lots of walkers.  I had even splits (first 13.1 the same as the 2nd 13.1) and crushed my goal time by 30".  And I stayed in my z2 HR zone.  I finished under 12 hours.

Galloway's website has more info on run/walk and suggested intervals for various paces.

TJ