# Shared breath of joy enhances empathy through breathing synchronization

## TL;DR

Synchronized breathing while observing joy increases empathy and familiarity, suggesting a physiological basis for emotional connection.

## Contribution

This study reveals that breathing synchronization enhances empathy specifically for joyful expressions.

## Key findings

- Synchronized breathing with joyful stimuli increased empathy and perceived familiarity.
- The effect was strongest for joy compared to other emotional expressions.
- A millimeter-wave radar system enabled non-perceptible real-time breathing monitoring.

## Abstract

Physiological synchronization has been observed in empathy. However, the specific role of breathing synchronization in emotional states remains unexplored. Here, we found that synchronized breathing that matches the observation of another person’s joyful facial expression increased empathy and perceived familiarity. In this study, we measured emotional arousal, familiarity, empathy, and favorability to participants while presenting face stimuli exhibiting six basic emotional expressions (i.e., neutral, joy, surprise, anger, fear, and sadness) under three conditions (i.e., static image, image with asynchronous breathing, and image with synchronized breathing in relation to the participant). In the synchronized condition, a high-precision millimeter-wave radar system was used to capture participants’ real-time breathing patterns, which allowed non-perceptible respiratory monitoring. Comparisons between emotional expressions revealed that the synchronized breathing condition with joyful stimuli was associated with the highest empathy and familiarity, which suggested that a physiological mechanism underlying shared breathing patterns facilitated emotional connection with joyful expressions. These findings offer insights into the embodied basis of positive emotional sharing underlying synchronized breathing during social activities, such as group singing and shared laughter.

The online version contains supplementary material available at 10.1038/s41598-026-34981-0.