Medical worker napping in hospital

Exhausted people have a lower tolerance for pain than those who have enjoyed a good night’s sleep. Credit: Andersen Ross/Getty

Neuroscience

A brain short on sleep dials up pain intensity

Brain region that naturally dampens pain falls short in those running an acute sleep deficit.

Poor sleep is known to amplify the experience of pain. Experiments in a sleep lab now suggest a reason why: in several brain regions, activity patterns in the sleep-deprived brain are different from those in the well-rested brain.

Matthew Walker at the University of California, Berkeley, and his colleagues allowed healthy adults to have one night of uninterrupted sleep and subjected them to one night of sleep deprivation. Both nights were followed by a morning pain test. The researchers held a heating element to each participant’s leg to determine the lowest temperature that the person found painful. Then the team applied these threshold temperatures while scanning participants’ brains.

When sleep-deprived, participants were sensitive to pain at lower temperatures than when they had slumbered soundly. Compared with well-rested brains, sleep-starved brains showed higher activity in the area that senses pain signals from the body — but lower activity in the area that normally raises levels of brain chemicals that provides natural pain relief.

Promoting healthy sleep may prove a useful strategy for managing pain, the authors say.