Those who have suffered insomnia for some time know from the marrow what science says about pain and lack of sleep: that the two go hand in hand and aggravate each other.
For example, people who suffer from chronic pain often lose the ability to sleep well; They usually attribute it to bad back, sciatica or arthritis. In turn, lack of sleep can make back pain feel worse and make it harder to sleep the next night, The New York Times reported.
It is not well known why lack of sleep worsens the sensation of pain, but it has to do with how the body responds to a wound, such as a cut or ankle sprain. It is felt when the nerves send vibrations through the spine to the brain. And there, a network of neural regions ignites in reaction to the wound and works to cope, or lessen, the sensation.
He considers that experience as a physiological dialogue between the unit deployed on the ground that has been attacked and the command center that tries to contain the damage. Now, in a new study, a team of neuroscientists has clarified the nature of the part of this exchange that comes from the command center and the effect of sleep on it.
In an experiment conducted in a specialized laboratory, the researchers discovered that a single night without sleep reduced the pain threshold of people by 15 percent and left an identifiable fingerprint in the part of the brain where the pain was recorded.
In another experiment, the team determined that small deviations in the average amount of sleep from one night to another predicted the total level of pain that person would feel the next day.
"The exciting thing about these findings is that they will motivate, and justify, more research to find out how this system works," said Michael J. Twery, director of sleep disorders at the National Heart, Lungs Institute. and the United States Blood (Twery did not participate in the study). "Once we understand how lack of sleep modifies the functioning of these patterns, we can deal with pain in a more effective way, whatever the type of pain."
Other researchers cautioned that the study was small and needed to be repeated on a larger scale. However, they said that at a time when chronic pain and addiction to narcotics are on the rise, this new study is a clear reminder that we can improve our body's ability to deal with pain without recipes. medical
The research team, led by Adam J. Krause and Matthew P. Walker of the University of California, Berkeley campus, had twenty-five adults go to the sleep lab on two occasions to measure their resistance to heat. Two readings were taken from each subject, one in the morning after they slept through the night and another in the morning after spending a sleepless night. The visits were made at least a week apart and included magnetic resonance measurements.
The subjects evaluated the sensation of pain that caused them to have a small warm pad on the skin, next to the ankle. By gradually adjusting the temperature, from hotter to colder, the researchers identified the level of pain each person rated as "unbearable": the maximum on a scale of one to ten.
Not sleeping all night increased thermal sensitivity the next morning, 15 to 30 percent more on the pain scale. This was not unexpected; Previous research had yielded similar findings in a variety of pain sensations.
But the brain images added a new dimension: for each participant, the activity intensified in the regions dedicated to the perception of pain, and collapsed in regions that help to manage or reduce it. Maximum activity occurred in the somatosensory cortex, a strip of neural tissue in the upper part of the brain.
There is the seat of the so-called cortical homunculus, a map or miniature representation of the body in the neural zones; it seems to be where the perception of pain becomes a conscious "auch". The lowest activity figures were recorded in deeper brain regions, such as the thalamus and the nucleus accumbens.
"Two things are happening here at the same time," said Walker, director of the Center for Sleep Sciences at the University of California at Berkeley. "There is a hypersensitivity to pain and also a loss of the natural analgesic reaction. The fact that these two things happened at the same time was surprising. "
The deliberate lack of sleep is not very common in other animals-squirrels, for example, are not usually unveiled to watch a television program, so perhaps in the process of evolution has not developed a backup system to help restore or calibrate the brain system dedicated to pain management, Walker surmised.
In another clinical study, the research team recruited 60 adults online who said they felt pain every day. Participants rated their level of sleep and pain over two days: in the morning they evaluated how they had slept the night before and then classified their level of pain in the afternoon.
For each individual, a poor quality night's sleep predicted higher scores on the daily pain scale. The critical factor was not how much time they slept, according to the study; what counted were the alterations to the deep sleep, the phase of the dream where almost does not dream, worth the redundancy.
The implications of this new finding are far-reaching. For example, the authors of the study indicated that in hospitals, where noise levels are high and interruptions are constant, earplugs and eye masks could be distributed as a low-cost solution to help patients recover and make shorter ones. the stays.
"The good news is that in the field of psychiatry and the study of memory it has already become very clear that sleep is a very important factor," said Robert Stickgold, assistant professor of psychiatry at the Harvard Medical School. "The bad news is that, on average, it usually takes ten years or more for the findings to go from research to practice."