Live sports spectating promotes oxytocin dynamics and heart rate synchrony in casual fans

Regular live sports spectating improves mental health through reduced loneliness, yet the neurobiological responses underlying these benefits during a single session remain unclear. Here, we tested whether live spectating elicits socio-physiological responses, oxytocin release and heart rate (HR) synchrony depending on baseline oxytocin levels. We measured HR and hormonal responses in 60 casual fans during live university basketball games. In the high-baseline oxytocin group (n = 30), oxytocin levels remained elevated throughout the games, whereas in the low-baseline group (n = 30), oxytocin increased to levels comparable to the high group, without increases in cortisol. Oxytocin promoted a sense of unity mediated by subjective enjoyment. HR synchrony during and after the games increased in both groups, associated with oxytocin levels. Finally, HR synchrony predicted psychological flow and team loyalty, mediated by unity. Our findings demonstrate that a single spectating session enhances social bonding through oxytocin dynamics linked to physiological synchrony.