Singing for 20 minutes—whether alone or in a group—lowers your stress hormones, and singing with others lowers them even more, which means singing itself helps calm your body, no matter if you're alone or with people.

The ideal study would recruit healthy adult participants and have each participant engage in three conditions in random order: 20 minutes of choir singing, 20 minutes of solo singing, and a 20-minute quiet rest control. Salivary cortisol would be measured before and immediately after each session. The comparison would test whether cortisol levels drop significantly more after choir singing than after solo singing or rest.

This study would follow two matched groups of adults—one that regularly sings in a choir and one that sings alone—over a 4-week period, measuring salivary cortisol after each 20-minute singing session. It would compare average cortisol reduction between the two groups to determine if social context influences the stress-reducing effect.

This study would observe naturally occurring singing behaviors in a community setting, measuring cortisol levels before and after 20-minute choir or solo singing sessions without randomization. It would compare the magnitude of cortisol reduction between the two contexts to test the claim’s association.

This would synthesize all published studies measuring salivary cortisol after 20 minutes of choir or solo singing in humans, pooling effect sizes to determine whether singing reduces cortisol and whether choir singing has a significantly larger effect than solo singing.

A pilot study measuring cortisol changes in a small group of participants before and after 20 minutes of choir singing and again after 20 minutes of solo singing, to estimate effect sizes and variability for future larger trials.