This 20 minute video was so interesting — The Longevity Metric Nobody Is Tracking (It’s Hiding in Your Smartwatch):

We’ll cover:

  • What heart rate variability actually measures
  • How the autonomic nervous system (sympathetic vs parasympathetic) controls it
  • Why low HRV predicts cardiovascular disease, sudden cardiac death, insulin resistance, and accelerated biological ageing
  • How HRV connects to inflammation (CRP), visceral fat, and metabolic health
  • What counts as a “good” HRV (RMSSD ranges explained)
  • How alcohol, poor sleep, stress, and overtraining suppress vagal tone
  • Science-backed ways to improve HRV — including Zone 2 cardio, VO₂ max training, breathwork, sleep optimisation, and stress regulation
  • How to use HRV as a daily behaviour feedback tool (without becoming obsessive)