HRV

Sleep Optimization for Longevity: The Complete Protocol

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Matthew Walker opens Why We Sleep with a statement that stopped many readers cold: “No aspect of our biology is left unscathed by sleep deprivation.” Sleep is the non-negotiable foundation of everything we’re trying to optimize for longevity. Every other intervention — exercise, cold exposure, sauna, fasting, supplements — builds on a baseline of adequate … Read more

Heart Rate Variability (HRV): What It Is and Why It Matters for Longevity

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Your heart doesn’t beat like a metronome. And that’s a good thing. The variation in time between consecutive heartbeats — a measurement called heart rate variability, or HRV — is one of the most sensitive windows into your body’s physiological state. High HRV signals a nervous system that’s adaptable, resilient, and well-recovered. Low HRV signals … Read more