Strict HR adherence during ultras

  • Creator
  • #64645

    During races (especially 24+ hour pushes), has anyone tried strictly keeping their heart rate at a constant number, ignoring all other signs of fatigue (except for injury)?

    With this method, you could minimize the risk of pushing too hard (above your AeT for long races) or underperforming. It shouldn’t matter what externality might be affecting your heart rate, be it caffeine, extreme heat, etc, your heart rate should tell you your true energy expenditure, right?

    This could be particularly effective in multi-sport races like “adventure races,” where power output is hard to gauge (paddling a canoe, for example).

    So, for me, could I simply try to keep my HR at 140 the entire race, the middle of my zone 1?

  • Participant
    rich.b on #64651

    I have found that in a race I can sustain a HR above what I could do in training, and at critical moments or challenging sections hit and sustain for a period of time HR values that in training would likely lead to blowing up. Also, it would be hard to determine what to set it at: for me, cruising on the flat at 5 min/km, HR is maybe 115 or so, and on a hard, reasonably long uphill push where I typically gain time and places I might be sustaining 145-150 (for me this is quite high, observationally my HR values and zones are seemingly very low compared to most others; your middle zone 1 is into my zone 4). Sometimes you also find that you are running in a small group that begins to split, and it can beneficial to stick with the fast train on that break when you sense those falling off the back would be too slow. If I were to stick to HR zones 1-2 then I would lose ground on the uphills and miss sticking with the right group. Last, I live at sea level, but have raced a few times at higher elevations (1000–3000 m), which adds complexity to setting HR values. Consequently I remain old school and have always relied in races on perceived effort – if I track HR, it is only for curiousity.

    AshRick on #64670

    My AeT HR (as defined here and confirmed at UC Davis lab) is 149. As Scott has written, now that I’m very fit, running at that HR is hard work. My “easy” long run HR is now around 135. I have a decent pace as low as 129. A year ago, 129 was walking.

    I plan to sit on about 130 HR on flats, and 35 on climbs, in the first 5-6 hours of my next 100. And then go largely on PE. The big advantage of watching HR early is the avoid going out too fast. At the start of a 100, we’re often in lifetime best shape, and fully rested for the first time in six months. It’s really easy to go too hard.

    On the other hand, Camille Herron says she just gets to 75% of her max HR and stays there. Works for her!

    robsinco on #64772

    Great question Eric! I think for ultras the HR is another tool in the chest for monitoring reasons, but nothing will beat just honing in to your breathing and how you feel. This might sound insane to you if you always track your HR every session but something that works for me is going out on a route I know with no strap, no watch, no monitorring, nothing but free flowing in the hills. It works for me and you tune into your senses when you need to back off and fuel etc. But I totally know that this is not good from a training monitoring side of things when I know a lot of us myself included can get caught up in the stat junky world! The issue with using it for the entire race could be simply explained by this scenario of having a bad sleep night before a race, combined with pre race nerves, your HR might be totally allover the shop, and cause you to trust on this and work well beneath your true race day potential. I try to never dip into super heavy breathing in long ultras until the last couple of hours and I dread to think what my HR would be if I trusted it then as you will know! Trust in your training buddy and have faith on race day, sometimes going with your gut can pay off

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