Selfless acts may be a natural painkiller, research suggests.
Scientists from Peking University in Beijing found people who perform kind gestures while expecting nothing in return are less likely to report discomfort when exposed to unpleasant conditions.
Doing good is thought to release the hormone dopamine, which has been shown to dampen chronic pain.
Altruistic people have been found to be happier, however, less was known about how selfless acts impact our perception of pain.
To learn more, the scientists carried out a series of experiments.
In the first, they compared people giving blood in response to an earthquake to those doing so after no natural disaster.
When asked to rate the pain of the needle, those who donated blood after an earthquake deemed it less uncomfortable, according to results published in the journal Proceedings of the National Academy of Sciences.
The scientists then exposed a group of people to cold conditions, some of which were volunteering to revise a handbook for migrant children.
Compared to those not carrying out the voluntary work, the “good samaritans” found the chilly temperatures more bearable.
In the third experiment, cancer patients who cooked and cared for others were compared against those who only looked after themselves.
Similarly, the more selfless individuals reported less pain.
In the fourth and final experiment, the scientists carried out scans to determine if doing good reduces pain signals in the brain.
Volunteers who donated money to orphans underwent an MRI while receiving electrical jolts.
Compared to people who did not donate, the volunteers showed less activity in the “pain centres” dorsal anterior cingulate cortex and bilateral insula when jolted.
The results also show the more the volunteers believed their donation was helping others, the higher the activity in their ventral medial prefrontal cortex.
This is thought to dampen down responses in the pain centres.
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The research comes after an expert from Columbia University in New York claimed kind people live longer.
“[Being kind] helps the immune system, blood pressure, it helps people to live longer and better,” Dr Kelli Harding, who penned the book The Rabbit Effect, told the BBC.
“It's pretty amazing because there's an ample supply and you can't overdose on it.”
Professor Daniel Fessler - from the University of California LA’s (UCLA) Bedari Kindness Institute - agreed, calling kindness “therapeutic”.
A team from Purdue University in Indiana also found those who volunteer have lower levels of the protein CRP, a marker of inflammation.
Inflammation has been linked to everything from depression and dementia to heart disease and even cancer.