Research suggests that people with Parkinson's disease can sing better.
A pilot study found that singing therapy led to fewer involuntary movements, improved mood and less stress.
The researchers cautioned that the first findings should be treated with caution, but said the benefits for patients matched those of taking medications.
Dr. Elizabeth Stegemoller, from Iowa State University in the United States, said: "We see the improvement every week when they leave the group of singers, it's almost as if they had a bit of heart in their steps.
Some of the symptoms that are improving, such as finger tapping and gait, do not always respond easily to medications, but with singing they are improving
Dr Elizabeth Stegemoller, Iowa State University
"We know they feel better and their mood is high.
"Some of the symptoms that are improving, such as finger tapping and walking, do not always respond easily to medications, but with singing they are improving."
Parkinson's disease causes a progressive loss of motor control, which leads to uncontrollable tremors, stiffness, slow movements and difficulty walking.
Problems of thinking and behavior may also occur.
Each year, around 145,000 people in the United Kingdom are diagnosed with Parkinson's.
The disease is linked to insufficient levels of chemical dopamine in the brain, but its causes are still not well understood. It is believed that genetic and environmental factors play a role.
Dr. Stegemoller's team studied 17 Parkinson's patients enrolled in a therapeutic singing group.
Measurements of heart rate, blood pressure and cortisol stress hormone levels of the participants were taken.
The three readings were reduced by singing, but not by an amount that reached statistical significance.
Researchers are studying the possible effects of singing on inflammation, neuroplasticity (the brain's ability to reconnect itself to compensate for injuries or illnesses) and blood levels of the oxytocin-binding hormone.
Dr. Elizabeth Shirtcliff, also of Iowa State, said: "Part of the reason why cortisol is going down may be because the participants in the song feel positive and less stressed in the act of singing with others in the group. This suggests that we can observe the oxytocin binding hormone.
"We are also looking at the heart rate and heart rate variability, which can tell us how calm and physiologically relaxed the individual is after singing."
Previous work by the same team found that singing can improve respiratory control and swallowing ability in Parkinson's patients.
The research was presented at the meeting of the Society for Neuroscience 2018 in San Diego.