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2008 Palo Duro Trail Run – Addendum

After dealing with some stomach issues during the Palo Duro 50 mile trail run, I decided to take a bit closer look at the heart rate data from my Garmin Forerunner 305.


Garmin 305 Data (click on thumbnail to see complete data)

The stomach cramps kicked in at the end of lap 3 (mile ~37ish) and looking at the heart rate data (red) from this lap (miles 25-37), it became pretty clear why it occurred; my heart rate was way too high based on the amount of calories I was consuming. Duh!

This course allows a person to run for nearly the entire race if they wanted to so there was plenty of running involved for me even though I did walk some of the hills. My heart rate danced in the 150s for most of the lap (section highlighted in yellow) and then hit 170 bpm over the last few miles. (Max heart rate is ~195 bpm)

Knocking down 200+ calories per hour at this effort leads to nothing but stomach issues for me. This effort is closer to what I would exert in a marathon and in those races, I am putting in 100-150 cals per hour without stomach issues. I have tried putting down 200 cals in an hour and I ended up dealing with cramp issues the rest of the run.

The other element that I feel didn’t help with the absorption is the amount of running I was able to do. If I was forced to do more hiking, I probably could have handled a higher calorie intake.

What what am I going to do about this?

I am going to try and implement the following nutrition and pacing guide for future 50 mile races:

  • 150-225 cals/hr for heart rate less than 145 bpm
  • 100-150 cals/hr for heart rate greater than 145 bpm
  • miles 1-25: maintain heart rate in the 130-145 bpm range
  • miles 26-50: Based on perceived energy levels, maintain heart rate in the 140-165 bpm range. If energy levels are low, reduce heart rate to the 130-145 bpm range and increase calorie intake.

This looks like it has enough geek-dome in it! Ready to give it a try…umm…next year.

What strategies have worked for your 50 mile races?

Happy Training!

About the author

David Hanenburg David Hanenburg is the passionate dirt-lovin' creator of Endurance Buzz and has been playing in the endurance sports world since 2000 after knockin' the dust off of his Trek 950 hardtail thanks to a friend asking to go ride some local dirt. In 2007 he ran his first ultra on the trails and fell in love with the sport and its people. For more information on David's endurance sports journey, check out the About page.

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