All of the subjects were fitted with intravenous catheters so blood samples could be taken immediately before the massage and up to an hour afterward.
To their surprise, the researchers, sponsored by the National Center for Complementary and Alternative Medicine, a division of the National Institutes of Health, found that a single session of massage caused biological changes.
Volunteers who received Swedish massage experienced significant decreases in levels of the stress hormone cortisol in blood and saliva, and in arginine vasopressin, a hormone that can lead to increases in cortisol. They also had increases in the number of lymphocytes, white blood cells that are part of the immune system.
Volunteers who had the light massage experienced greater increases in oxytocin, a hormone associated with contentment, than the Swedish massage group, and bigger decreases in adrenal corticotropin hormone, which stimulates the adrenal glands to release cortisol.
The study was published online in The Journal of Alternative and Complementary Medicine.
The lead author, Dr. Mark Hyman Rapaport, chairman of psychiatry and behavioral neurosciences at Cedars-Sinai, said the findings were “very, very intriguing and very, very exciting — and I’m a skeptic.”