When people sing in a choir and feel happy or emotional, their body’s first line of defense in the mouth and nose (called S-IgA) seems to change too—suggesting that how we feel emotionally might be connected to how our body fights off germs.

Whether fluctuations in S-IgA levels correlate with moment-to-moment changes in self-reported or physiologically measured emotional states during actual choir rehearsals or performances.

Whether sustained participation in choir activity leads to consistent patterns of S-IgA change alongside reported emotional well-being over time.

Whether individuals who report consistently high emotional engagement during choir have different baseline or average S-IgA levels compared to those reporting low emotional engagement.

Whether a single choir performance triggers immediate changes in S-IgA concurrent with emotional arousal.

Whether choir participation itself, independent of emotional state, influences S-IgA levels.