Bad sleep increases sensitivity to pain

Too little sleep can lead to more severe pain?

Pain can severely affect sleep and keep people awake for a long time. But how does it affect perceived pain when people often sleep poorly? Neuronal disorders in the brain have now been detected in sleep deprivation. Such disorders increase and prolong the pain of injuries and illnesses.

The researchers at Berkeley University found in their recent research that poor sleep affects, and even aggravates, pain they suffer. The physicians published the results of their study in the English journal "Journal of Neuroscience".

Sleep and its effects on pain

The scientists have proven their hypothesis that sleep deprivation can increase pain sensitivity, as evidenced by an accelerated response in the so-called somatosensory cortex of the brain. Also surprising was the impaired activity in the nucleus accumbens, a region of the reward circuit of the brain. This region, among other functions, also increases dopamine levels to relieve pain. "Sleep disorders not only amplify the pain-sensitive regions in the brain, but also block the natural analgesia centers," said Professor Matthew Walker of the University of Berkeley in a press release. When poor sleep increases sensitivity to pain, sleep has to be taken much more into account in the treatment of patients, especially in hospital wards, the expert continues.

Lack of sleep may misjudge pain signals

Another important brain region negatively affected in the brain by sleepless people was the insula, which evaluates pain signals and places them in context to prepare the body for the reaction. It is a critical neural system that assesses and categorizes the pain signals and allows the body's natural painkillers to relieve pain, the researchers explain.

Changes in sleep had a big impact

To test the connection between sleep and pain in common everyday scenarios, researchers surveyed more than 230 adults of all ages across the country. Respondents were asked to indicate their nocturnal sleep hours and their daily pain levels over a few days. The results showed that even minor shifts in sleep and wake patterns correlated with changes in pain sensitivity.

First, the baseline pain threshold of the subjects was determined

For their study, the physicians recruited 25 healthy young adults who did not suffer from sleep or pain disorders. Since different people have different pain thresholds, the researchers first recorded the baseline pain threshold of all study participants after a full night of sleep. For this purpose, the heat occurring under the left leg of the subjects was gradually increased, while the brain activity was recorded by a functional Magnetic Resonance Imaging Scanner. Participants rated the onset of heat pain on a scale of one to ten and averaged thermal discomfort at about 111 degrees Fahrenheit (about 44 degrees Celsius)..

Too little sleep increased the sensitivity to pain

After assessing the baseline sensitivity of all participants after a long night's sleep, the experts were able to compare how this threshold changed by repeating the procedure after a sleepless night in the patients. So they found out that the vast majority of people suffering from lack of sleep already felt pain at about 107 degrees Fahrenheit. The entire group felt uncomfortable even at low heat, indicating that their own sensitivity to pain had increased after inadequate sleep, say the authors. The brain assesses the pain differently without adequate sleep. In the meantime, after a sleepless night, imaging of the brain showed marked activity increases in the somatosensory cortex and deactivation in the nucleus accumbens and insular cortex, signaling malfunction in the nerve mechanisms controlling the physiological responses to painful stimuli, the medical community explains.

Sleep is a natural analgesic

Sleep is a natural analgesic, so to speak, which can help alleviate pain, says Professor Walker. "Our findings suggest that patient care would be significantly improved and hospital beds would be cleared sooner if uninterrupted sleep was considered an integral part of health management," adds the expert. (As)