Sparkling Water Co-Consumption Enhances Oxytocin-Linked HR Synchrony and Social Connection in Live Sports Spectatorship

Live sport spectatorship can promote social connection, yet scalable, low-burden strategies to strengthen bonding in real-world spectator settings remain limited. We here tested the hypothesis that co-consuming sparkling water during spectating attenuates hunger and fatigue and strengthens enjoyment and perceived unity, potentially via HR synchrony linked to oxytocin dynamics. In an individually randomized field experiment at a collegiate women’s basketball home game (sparkling water: n = 21; plain water: n = 19), spectators consumed 200 mL of sparkling water or plain water in synchrony before tip-off and before the end of halftime, with additional ad libitum intake of the assigned beverage permitted thereafter. We assessed acute freshness and hunger, repeated fatigue and enjoyment, interpersonal HR synchrony from the first half to 15-min post-game, perceived unity toward players and fellow spectators, and salivary oxytocin levels. Relative to plain water, sparkling water increased freshness and reduced hunger after intake, attenuated post-game fatigue, and enhanced enjoyment and perceived unity. HR synchrony was preserved in association with attenuated post-game fatigue after the game, and sustained synchrony was associated with higher perceived unity. Oxytocin decreased more in the sparkling-water group, and this decrease was associated with preserved HR synchrony as well as with changes in unity toward fellow fans. These findings support our hypothesis and suggest that co-consuming sparkling water serves as an alcohol-free, low-burden ritual to enhance social connection during and after live sport events. Highlights - Sparkling water increased freshness and reduced hunger after intake in spectators. - Sparkling water attenuated the post-game increase in subjective fatigue. - Sparkling water increased enjoyment and perceived unity. - Post-game HR synchrony was preserved in association with lower fatigue and higher unity. - Oxytocin decreased more with sparkling water and tracked HR synchrony and fan unity. - Co-consuming sparkling water is a low-burden, alcohol-free ritual for social connection.