The Healthy Chaos Your heart is not a metronome. If it were, you'd be in serious trouble. The healthy heart speeds up and slows down constantly, responding to breath, to thought, to emotion, to movement, to a thousand signals from your environment and inner state. This variation between beats, measured in milliseconds, is called heart rate variability, and it may be the single most important biomarker you've never heard of. High variability indicates a nervous system that's f

You will take approximately 20,000 breaths today. Right now, as you read this sentence, you're breathing. Yet you probably weren't aware of it until this moment. That breath you just took, the one you're taking now, represents something extraordinary: a voluntary action you can control that directly influences involuntary systems you normally cannot. Your breath is the only bridge between your conscious and unconscious nervous systems. It's the mechanism through which you can