Breathing rate during ultramarathons

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  • #55080

    I have noticed during long trail running races in the mountains that after 8-10 hours of running/power-hiking that my breathing rate goes up significantly while everything else seems to slow down. I would like to understand what is going on so that I can adjust my training to go past what feels like a performance bottleneck.

    So this is how a race (>100km with a lot of height gain) typically looks like for me:
    1. 8-10 hours where HR slowly but surely goes down (from high Z2 to a low Z1), high-to-moderate power output, “normal” breathing rate (i.e. breathing is proportional to HR)
    2. 10 hours (or more…) with relatively steady HR (low Z1), moderate-to-low power output, high breathing rate (feels similar to a Z3 workout, but HR is definitely in Z1 or below and pace is rather slow).

    I have some issues with alimentation, typically finding it harder and harder to regularly ingest carbs during long races (a rather common issue I suppose) and I was wondering if that could be linked to this high breathing rate or there is another cause. Some kind of respiratory fatigue or inefficiency kicking in, perhaps?

    So my questions are:
    – is it typical to experience high breathing rate together with low heart rate in the second half of a 20h run?
    – can that be improved with some sort of training?

  • Moderator
    Thomas Summer, MD on #55168

    Hi Sylvain!

    Good question!

    Your reactions are quite normal.

    The high breathing rate is mostly caused by fatigue of the respiratory muscles. Here is an interesting paper:
    “Our results suggest that expiratory pulmonary capacity and lower-limb strength are more fatigued following a longer MUM, while inspiratory strength loss is independent of distance.”
    You can train your respiratory muscles with special devices. I had good results with that. It’s cheap and not much risk, so I would recommend you try that.

    breathe like your life would depend on it!

    Sylvain on #55184

    Hi Thomas,

    Thanks a lot for the answer! Expiratory pulmonary fatigue, as shown in that paper, does explain perfectly what I have experienced. It all makes sense now 🙂
    I will follow up on trying to train respiration with some special devices.

    and yeah, breathing does sound like an important thing to do! 🙂

    thanks again!

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