SelfSenseSelfSense HRV

How to Use SelfSense

Welcome to SelfSense! This guide will help you get started with the app and make the most of its features.

SelfSense is not only about HRV — it also tracks adaptive movement variability on accelerometer and gait data, so you can see how adaptive your body is across both cardiac and motor domains.

You can use SelfSense to:

  • Track your HRV (heart rate variability and its fractal dynamics)
  • Track your movement variability (accelerometer and stride intervals, with DFA alpha)
  • Practice breathing and movement sessions that make your HRV and motion more adaptive

How Is SelfSense Different?

SelfSense is different from other apps because it combines both the entrainer and the tracker, so you can trace how your sessions affect your HRV and choose the most suitable mode for you.

Unlike other HRV tracking apps, SelfSense also measures fractality of your HRV using DFA — an algorithm widely used in medical science and fitness to estimate how resilient and adaptive your system is. Most apps focus on the absolute value, SelfSense helps you understand the dynamics.

Getting Started

Download SelfSense from TestFlight and install it on your iPhone. The app also works with Apple Watch for a more immersive experience. You can install it to your Apple Watch as well and use it independently from your iPhone.

Connecting Your Devices

SelfSense works with:

  • Apple Watch — For real-time HRV tracking, haptic feedback, and movement variability via the built-in accelerometer (standalone or paired with iPhone)
  • Polar H10 — For ECG-quality heart rate monitoring
  • Movesense sensors — Stream accelerometer data over OSC/UDP to track movement variability from any body part (chest, hip, ankle) for gait and posture analysis

Start an HRV Tracking Session

  1. Open the app on your iPhone
  2. Open the Tracker tab
  3. Choose your device: Apple Watch or Polar H10
  4. Wait until the device is connected
  5. Your most recent reading will be shown
  6. If no data exists yet, you will be prompted to perform a recording session
  7. Once the recording is done, usually after about 2 minutes you start, you will have meaningful feedback: whether you are in recovering state, adaptive mode, or in a state of tension. Use the advice feature to get an insight into the kind of behavior you can engage in to optimize your HRV pattern.

Starting an HRV Entrainment Session

  1. Open the app on your iPhone
  2. Optionally: measure your HRV before the session using the Tracking tab above and get insights about your current state.
  3. Open the Entrainer tab
  4. Select your preferred breathing mode. Default is Deep Breathing.
  5. A unique fractal breathing pattern will be generated. The corresponding alpha value, a chart of the values generated, and the remaining time will ne shown as the session begins.
  6. Follow the instructions: inhale when the circle expands, exhale when it contracts
  7. Haptic feedback and optionally sound can be used to follow the breathing pattern
  8. Once you are done, you can record a tracking session again
  9. Find the mode that optimizes your HRV fractality. While your absolute HRV value may decrease during breathing, you are looking for a mode of breathing that brings your alpha1 DFA component close to 1 — this is when your body is at its most adaptive state.

Track Movement Variability

In addition to HRV, SelfSense can measure the fractal signature of your movement:

  1. Open the Sensor tab on your iPhone or Apple Watch
  2. Choose Movement mode for continuous accelerometer magnitude (standing, sitting, general activity) or Gait mode for stride-interval tracking while walking or running
  3. The app computes DFA alpha1 on a rolling 128-sample window and shows you the same adaptive / rigid / random state indicator as the HRV tracker
  4. Use this during movement practice, walks, or training to see when your body is in its adaptive sweet spot (α₁ ≈ 1.0)

Read more in the Adaptive Movement Variability guide.

Tips for Best Results

  • Find a quiet, comfortable place
  • Practice regularly for best results
  • Start with shorter sessions and gradually increase duration
  • Try out the movement sessions. During the sessions, you can use the haptic feedback to count steps: e.g. two steps every vibration - inhale, two steps every vibration - exhale.

References

The science behind the metrics and protocols in this guide is covered in the linked articles on fractal HRV and adaptive movement variability. Foundational sources:

  • Hardstone, R., et al. (2012). Detrended Fluctuation Analysis: A Scale-Free View on Neuronal Oscillations. Frontiers in Physiology. — the DFA algorithm SelfSense applies to both HRV and movement.
  • Hausdorff, J. M., et al. (1996). Fractal dynamics of human gait. Journal of Applied Physiology. — long-range correlations in stride intervals (gait-mode reference).
  • Stergiou, N., & Decker, L. M. (2011). Human movement variability, nonlinear dynamics, and pathology. Human Movement Science.
  • Dierick, F., Nivard, A.-L., White, O., & Buisseret, F. (2017). Fractal Analyses Reveal Independent Complexity and Predictability of Gait. Scientific Reports.
  • Werner, G. (2010). Fractals in the Nervous System. Frontiers in Physiology.
  • Löfblom, J. (2019). Prototyping with Movesense Platform — Breathing Application. — reference on simultaneous HRV and breathing capture from a single chest-worn sensor (the Movesense workflow used here).
  • Paranyushkin, D. (2025). EightOS: Variability in Physical Practice; SelfSense: Body-Network Isomorphism and Movement Signatures (2026). — the fractal breathing protocol and the four variability states (uniform / regular / fractal / tension) shown in the app.