Experiencing acute pain can alter how people perceive the size and shape of their bodies and reduce satisfaction with their appearance, according to a study by researchers from the Jagiellonian University, the Academy of Physical Education in Katowice and the University of Lübeck.
The findings, published in the journal Pain, showed that experimentally induced pain caused participants to perceive the painful part of the body as larger and led to lower overall body satisfaction.
Researchers analysed how acute pain affects body image and sensory perception using a controlled experiment involving more than 90 participants without chronic pain. One group received a saline injection into the lower back that caused short-term pain, a second group received a simulated painless injection, and a third group served as a control.
The study found that only participants experiencing actual pain reported distortions in body perception.
“In everyday life, we do not notice this nature of body perception because the brain performs its functions extremely efficiently. However, under certain conditions, for example, under the influence of pain, distortions can occur,” said Aleksandra Budzisz, a psychologist at the Institute of Psychology at Jagiellonian University and the study’s lead author.
Participants in the pain group perceived their lower backs as larger than before, particularly on the right side of the body. Researchers suggested this may indicate that the dominant side plays a greater role in the somatosensory system, which processes bodily sensations.
The authors said the results support the theory of “somatosensory magnification,” according to which pain can expand the perceived size of a body part through changes in the brain’s sensory processing systems.
Previous studies involving chronic pain patients have found similar distortions. People suffering from osteoarthritis and other conditions have described painful body parts as swollen, heavier or less connected to themselves, even when no physical swelling was present.
“In terms of the body's functioning, this makes profound sense. A change in body perception may prompt more cautious movement, avoiding contact, or protecting a given body part. In the short term, this mechanism is adaptive and increases our chances of avoiding more serious damage,” Budzisz said.
The researchers emphasized that the findings suggest pain affects not only the body itself but also the brain’s representation of the body.
The study also pointed to possible therapeutic applications. Existing treatments such as mirror therapy, in which patients observe the reflection of a healthy limb to ease pain in an affected one, already use the relationship between perception and pain. Similar approaches include imagery techniques and body awareness training.
According to the researchers, effective pain treatment should consider not only the physical source of pain but also how the brain processes and interprets bodily sensations.
Ewelina Krajczyńska-Wujec (PAP)
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