Fading during an Ironman

The following heart rate data is from a 34 year male triathlete during the Great Floridian triathlon in Clermont, Florida on Oct. 21, 1995. The distances were 2.4mi/112mi/26.2mi -- a standard "Ironman" distance event. The morning hours were dominated by a very strong wind, and in the afternoon it calmed down and was quite sunny and warm.

    The following points can be extracted from the race and data;
  1. There is an apparent slow decline of heart rate during the race. Note: This is accentuated by the occurence of steep hills during the first 30 miles of the bike and first 5 miles of the run -- which would be expected to result in higher heart rate peaks during climbing. Averaging this data in with data from relatively constant effort during latter flat portions would be expected to exaggerate any apparent average downward drift in heart rate. To help correlate data and "feel", the triathlete did experience fatigue during the last 20 miles of the bike and last 1/2 of the marathon. The last half of the marathon was much slower than the first (1:45, 2:05). This is not ideal. The best races usually come from even or negative splits. Going out too hard is the most common mistake made by Ironman triathletes. It is very important to realize that too hard a bike means too slow a run.
  2. The data from the flat portion of the bike course show a reasonably constant heart rate despite strong wind. The windy conditions resulted in both strong headwinds and tailwinds during the bike course. The lesson from this is that efficienicy is critical during an ultra-distance race. Tailwind or headwind, maintaining a constant heart rate -- in a range that you know you can sustain for a very long time -- is crucial to surviving these races.