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💓 Heart Rate Variability: Measuring the Balance of the Autonomic Nervous System

Explore heart rate variability (HRV), the beat-to-beat fluctuation in heart rhythm driven by the tug-of-war between the sympathetic and parasympathetic nervous systems, and how metrics like RMSSD turn that fluctuation into a real, measurable signal of stress and recovery.

Medical Technology & Imaging Physics3DModerate60 FPS

The simulation animates a beating heart alongside a live R-R interval trace, showing how simulated sympathetic and parasympathetic activity stretch and compress consecutive beat intervals, while a running RMSSD calculation and a frequency-domain LF/HF breakdown update in real time as the balance shifts.

🔬 What It Demonstrates

🎮 How to Use

Adjust the sympathetic and parasympathetic activity sliders to simulate stress versus relaxation, press play to watch the R-R interval trace and heartbeat animation respond beat by beat, and observe how the computed RMSSD value and the LF/HF frequency split change as the autonomic balance tips one way or the other.

💡 Did You Know?

Elite endurance athletes often show resting RMSSD values several times higher than sedentary individuals of the same age, and many use daily morning HRV readings, taken lying down right after waking, as an early warning system for overtraining before performance or mood even start to suffer.

⚙ Under the hood

heart rate variabilityhrvautonomic nervous systemrmssdbiofeedbackphysiologymedtech

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install