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MultiHR
Heart rate comparison toolkit
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Guide

MultiHR Tutorial

A practical guide to device connection, single-device monitoring, aligned comparison recording, export, and analysis in MultiHR.

Introduction

MultiHR is a heart rate monitoring and analysis app for iOS and Android. It can monitor and record data from multiple Bluetooth heart rate devices at the same time, visualize live heart rate curves, export sessions, and run comparison analysis inside the app.

Important: MultiHR is intended for research workflows and device evaluation. It is not a medical product and must not be used for diagnosis, treatment, or clinical decision-making.

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Key Features

  • Simultaneous multi-device connection and monitoring
  • Real-time heart rate visualization
  • Automatic single-device recording for review, export, and keepalive
  • Manual aligned recording for multi-device comparison
  • Excel and CSV export
  • Pearson correlation and Bland-Altman analysis
  • Support for mainstream BLE heart rate devices that expose the standard 0x180D Heart Rate service

How to Use MultiHR

Device Connection

  1. Launch the app and tap the search icon to scan for devices.
  2. Find your heart rate device in the available device list.
  3. Tap Connect to establish the BLE connection.
  4. Connected devices appear in the connected devices list.

Data Recording

  • Single-device real-time monitoring already counts as a recording session. When one device is connected, MultiHR automatically records that session for review, export, and keepalive.
  • You do not need to tap the manual record button for one-device monitoring.
  • When multiple devices are connected and you need aligned comparison data, tap the record button to start one aligned recording session.
  • Watch live heart rate curves during the aligned recording.
  • Tap the record button again to stop the aligned session.
  • After stopping, choose Export as Excel, Export as CSV, Analyze data, or Discard data.

Background Keepalive and Live Status

  • On iPhone, when Live Activities are supported and enabled, MultiHR can keep the current monitoring or recording session visible with Live Activity and Dynamic Island.
  • On Android, MultiHR uses foreground-notification style keepalive while devices remain connected, and supported systems may surface a stronger live status presentation.
  • If you see a recording indicator while monitoring a single device, that is expected. The app is automatically recording the current monitoring session.
  • The manual record button is for aligned multi-device recording, not for toggling one-device live monitoring.

Data Analysis

MultiHR assumes you are comparing at least two devices. One device acts as the reference, while the others act as test devices. A typical example is a Polar H10 chest strap as the reference device and an optical armband as the test device. For meaningful comparison analysis, connect every required device first and use one aligned recording session.

Pearson Correlation Coefficient Analysis

  • The Pearson coefficient measures linear correlation between two devices.
  • Range: -1 to 1
  • 1 means perfect positive correlation.
  • -1 means perfect negative correlation.
  • 0 means no linear correlation.
  • |r| >= 0.8 is usually treated as strong correlation.
  • 0.5 <= |r| < 0.8 is moderate correlation.
  • |r| < 0.5 is weak correlation.

Bland-Altman Analysis

  • Bland-Altman plots assess agreement between two measurement methods.
  • The x-axis shows the mean of the two measurements.
  • The y-axis shows the difference between the two measurements.
  • The center line shows the mean difference.
  • The upper and lower lines show the 95% limits of agreement.

Data Export

Two export formats are supported:

  • Excel (.xlsx): detailed timestamps and per-device columns
  • CSV: portable format for import into other tools

Important Notes

  • Make sure devices are charged before starting.
  • Enable Bluetooth and wear the sensors correctly.
  • Keep devices within range during monitoring or recording.
  • Maintain stable BLE conditions for cleaner results.
  • Longer comparison sessions are usually better. More than 5 minutes is recommended when the protocol allows it.
  • MultiHR focuses on standard BLE heart rate devices using 0x180D. Apple Watch is not directly supported through that profile.
  • Interpret all results in the context of the specific test protocol.