This isn't your typical choir practice.
And it’s not held in a traditional practice space.
These singers are all dealing with cancer, theirs or a loved one’s.
"There are people in our choirs who are undergoing treatment right now.
There are some people who are waiting for treatment."
Rosie Dow leads the choir groups at Tenovus Cancer Care, in the U.K.
"We do have some terminally ill patients as well in our choirs, so people in palliative care.
And then we also have people who've lost people to cancer.
So carers and supporters."
Anecdotally, chorus members have said that belting out tunes makes them feel good.
But Dow and her colleagues wanted to see if that psychological effect might translate to a biological effect.
So they selected five choir groups in Wales—with a total of 193 singers—and took saliva samples both before and after an hour of singing.
They found that singers had significantly lower levels of the stress hormone cortisol after the session than they’d had prior to choir.
Along with an increase in proteins called cytokines—which the researchers say might suggest a boost in immune activity.
The results are in the journal eCancer Medical Science.
It's still not clear whether those biochemical changes translate to any better outcome for patients.
And choir practice is in addition to—not instead of—conventional treatments.
"Of course we wouldn't recommend it as an alternative to chemotherapy or radiotherapy or surgery or any of the other conventional cancer treatments, but in terms of people's mental health, this might be a good complement to the treatment that they're having."
Next up, the researchers will conduct a follow-up study at the U.K.'s biggest cancer center to see if these biological changes hold up over the long term.
After all, singing is certainly a cheap treatment.
And it does no harm, either…as long as you don't wail too hard.