# Validity of the Polar H10 for Continuous Measures of Heart Rate and Heart Rate Synchrony Analysis

## TL;DR

The Polar H10 chest strap accurately measures heart rate and heart rate synchrony between individuals, making it a practical and low-cost alternative to traditional ECG systems for physiological research.

## Contribution

This study confirms the Polar H10's validity for measuring both individual heart rate and dyadic heart rate synchrony in real-world settings.

## Key findings

- The Polar H10 showed almost perfect agreement with a reference ECG system for individual heart rate measures.
- Dyadic heart rate synchrony metrics from the Polar H10 were highly correlated with those from the ECG system.
- The device is a reliable, low-cost alternative for physiological research in ecologically valid settings.

## Abstract

What are the main findings?
The Polar H10 chest strap showed almost perfect agreement with a reference Lead II ECG system for both individual heart rate measures (aggregate and moment-to-moment) and dyadic synchrony measures, with small systematic biases.Dyadic heart rate synchrony metrics derived from the Polar H10 were almost perfectly correlated to those from the Lead II ECG system, with no significant bias.

The Polar H10 chest strap showed almost perfect agreement with a reference Lead II ECG system for both individual heart rate measures (aggregate and moment-to-moment) and dyadic synchrony measures, with small systematic biases.

Dyadic heart rate synchrony metrics derived from the Polar H10 were almost perfectly correlated to those from the Lead II ECG system, with no significant bias.

What are the implications of the main findings?
The Polar H10 offers a valid, low-cost, and practical alternative to traditional ECG setups for studying both individual and interpersonal physiology.Although further testing is warranted, this could facilitate broader applications in cognitive, affective, and social neuroscience, enabling research to extend beyond tightly controlled laboratory settings into real-world environments.

The Polar H10 offers a valid, low-cost, and practical alternative to traditional ECG setups for studying both individual and interpersonal physiology.

Although further testing is warranted, this could facilitate broader applications in cognitive, affective, and social neuroscience, enabling research to extend beyond tightly controlled laboratory settings into real-world environments.

Heart rate (HR), a non-invasive indicator of physiological arousal and autonomic nervous system engagement, is widely used in cognitive and affective sciences to monitor individual responses and interpersonal synchrony in dynamic emotional and social contexts. Recent advances in wearable sensors have enabled researchers to assess HR synchrony in ecologically valid settings. In this study, we replicate prior validations of the Polar H10 chest strap for individual HR measurement and extend these findings by evaluating its validity for measuring HR synchrony between individuals. Dyads completed a previously validated experimental task designed to elicit HR fluctuations while jointly attending to emotionally evocative, 5-min audiovisual stimuli. First, we observed high correspondence (Pearson’s r > 0.99) between the Polar H10 and a gold-standard ECG system in measuring individuals’ HR, both at the aggregate and moment-to-moment levels, thus confirming and extending prior findings. Second, we found high correspondence (Pearson’s r > 0.95) between the two systems in quantifying dyadic HR synchrony using multiple analytical approaches. These results support the use of the Polar H10 as a low-cost, easy-to-use, and reliable tool for both individual and dyadic HR measurement. This represents an important step toward establishing its applicability in real-world settings where traditional ECG systems are impractical.