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The Big Holes in Wearable Heart Rate Variability And Readiness Scores

Eric Topol · 19 Sept 2026

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Every claim below was made in this piece, quoted word for word and numbered in the order the piece makes them, so you can read it there rather than take our word for it. The sentence above each quote is our reading of the claim, not their wording. Each quote was checked against a stored copy of the page at build time; where the two differ, the quote is the fact.

  1. Our reading

    Raising your heart rate variability does not mean your health outcomes will improve, because HRV is a surrogate marker without an established causal link.

    Their wordsAn important reminder is that HRV is a surrogate marker without any established cause-and-effect relationship. If you increase your HRV, that doesn't mean it will improve health outcomes.

  2. Our reading

    Wearable readiness scores are not ready to be relied on, because they are proprietary and built mostly on metrics that have their own problems.

    Their wordsFrom the points I've gone over above, we're not ready for readiness scores. Besides being proprietary, they are predominantly based on metrics that have their own issues.

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