Topic
HRV
Heart rate variability, autonomic balance, and recovery monitoring.
Max KlineDoes Drinking Earlier in the Evening Actually Protect Your Overnight Heart Rate?
A 20,968-person wearable study found each extra drink tracked with about 2.8 bpm higher overnight resting heart rate and 3.8 ms lower HRV, measured against each person's own sober nights.
Atlas MercerCan You Trust Your Oura or Whoop Readiness Score?
When five wearables were tested against a clinical ECG across 536 nights, the raw nocturnal heart rate and HRV signals proved accurate to within a few percent, accurate enough to build a protocol on.
Max KlineDoes Taking Ashwagandha Actually Lower Your Cortisol, or Is That a Myth?
Ashwagandha is the supplement everyone's stressed friend recommends, and the pitch is always the same: it drops your cortisol. That's a specific, testable claim, so let's treat it like one. The most-cited human trial…
Max KlineDoes Wearing Earplugs and an Eye Mask in the ICU Actually Prevent Delirium? What the Sleep Data Shows
Here's a finding that hit me sideways because it's so low-tech it feels almost insulting: a randomized trial found that giving hospital patients earplugs, an eye mask, and a scheduled quiet period at night measurably…
Max KlineDoes Breathing Through Your Nose During Sleep Actually Change Your Oxygen and Heart Rate?
Here's a variable most people never isolate: which hole you breathe through at night. Mouth breathing during sleep isn't just a snoring nuisance — it correlates with drier airways, more arousals, and worse subjective…
Max KlineDoes Eating a Big Dinner Late at Night Actually Worsen Your Overnight Heart Rate Variability?
Here's a variable most people ignore when they stare at their morning HRV: what time they stopped eating the night before. I got curious after a string of days where my Oura readiness tanked despite decent sleep durat…
Atlas MercerThe Parasympathetic Trap of Heart Rate Variability
The default assumption in wearable analytics is that a higher heart rate variability indicates a higher state of recovery. This is a heuristic, and heuristics fail at the margins. Willpower will convince you to train…
Max KlineWhy Your Dim Nightlight Is Wrecking Tomorrow's Glucose Response
We usually think of light timing purely in terms of melatonin suppression and sleep architecture. But recent data shows a much more direct, mechanical link to autonomic tone and metabolic function. A fascinating study…
