The study was conducted with a group of 3-year-olds waiting to receive heart transplants. Parents sang to their children and researchers monitored their heart rates and pain perception.
The results were compared to those of children in two other groups, one in which parents read to children and another in which the children were left alone.
Only those who had been sung to showed a reduction in pain or heart rate.
"It shows that children can be affected physiologically by music," said professor David Hargreaves of Roehampton University, one of the study’s authors.
"The practical applications are fairly obvious. Music therapists are going to be a lot cheaper than drugs to numb pain," Hargreaves added.
Professor Tim Griffiths, a consultant neurologist with the Wellcome Trust, told BBC Radio 4 that the limbic system, an ancient part of the brain, is responsible for the emotional response to music.
"What I think is happening here is that the emotional part of the brain is being stimulated by music, more so than the reading stimulus," he said of the study. “This is decreasing the arousal level, and that in turn is affecting their pain response levels.”