Study reveals laughter really is the best medicine
Baku, September 15 (AZERTAC). People feel less pain after a good laugh, because it may cause the body to release chemicals that act as a natural painkiller, research has suggested.
The researchers at the University of Oxford also think the ability to belly laugh was unique to early humans.
This, they believe, enabled our ancestors to form much larger tribal groupings than the ape-like species that lived alongside them.
The research is published in the Proceedings of the Royal Society B.
The experimenters first tested the pain thresholds of volunteers.
They were then split into two groups, with one being shown 15 minutes of comedy videos, while the other was shown material the researchers deemed boring - such as golfing programmes.
The researchers found that those subjects that had recently experienced belly laughs were able to withstand up to 10% more pain than they had done before watching the videos.
To their surprise, the scientists also found that the other group was less able to bear pain after watching 15 minutes of the "boring" programmes.
The type of laughter was also important. Tittering and giggling did not elicit any physiological effect; only a good guffaw did the job.
Professor Robin Dunbar of Oxford University, who led the research, believes that uncontrollable laughter releases chemicals called endorphins into the body which, as well as generating mild euphoria, also dull pain.
"It`s exactly what happens when we say `I laughed until it hurt`. It seems to be extremely painful and it`s that pain that produces the endorphin effect," he said.
However, not all the comedy programmes were able to hit the spot, according to Prof Dunbar.
Slapstick humour seemed to score highly whereas clever stand-up comedy routines, though found to be enjoyable, had no effect on raising pain thresholds.
"Things that worked very well were slapstick comedies such as Mr Bean.
"Situation comedies such as Friends also seemed to be particularly successful."
The researchers were not able to measure endorphin levels directly because that would have involved extracting fluid from the volunteers` spines using a long needle - a process which, Prof Dunbar concedes, would quickly take the smile off their faces and possibly influence the results.
Instead, the researchers took what they referred to as a proxy measurement, which tested the pain threshold for each volunteer.
This involved, for example, placing a bag of ice on their arms to see how long they could withstand it.
The greater the increase in pain threshold, the greater the amount of endorphins produced.
The aim of Prof Dunbar`s study is not to develop a new treatment.
Instead, it is to explore the role of laughter in the establishment of human societies two million years ago.
All apes are capable of laughter, but it is only humans that are able to belly laugh and so release endorphins.
Prof Dunbar`s theory is that as well as dulling pain, endorphins also make people more susceptible to developing bonds.