PhotoAlto/Frederic Cirou

Can’t sleep? If darkening the room doesn’t help, you might try a cooling cap.

Researchers from the University of Pittsburgh School of Medicine reported this week at the annual meeting of the Associated Professional Sleep Societies (APSS) that keeping the brain cool may help people with insomnia to catch more z’s.

Dr. Daniel Buysse, a psychiatrist at the university, had already shown in previous studies that those with insomnia tend to have higher than normal activity in the frontal lobes of their brains, the regions responsible for higher-order functions like planning, organizing and logical reasoning. Many insomniacs say they can’t fall asleep because their brains keep working, and they can’t shut off these thought processes. Buysse wondered whether the added activity was also raising the brain’s temperature to the point at which sleeping was physiologically more difficult. The body’s circadian clock, which regulates sleep and wakefulness, keeps the body at its warmest during the day and starts to lower body temperature in the evening to help us doze off. For those with insomnia, however, researchers found that the extra brain activity was keeping the brain too hot to sleep.

When Buysse’s group gave 12 insomniacs a cap to wear that contained circulating water at cool temperatures, they were able to get them to fall asleep almost as easily as people without sleep disorders: using the caps, the insomniacs took about 13 minutes to fall asleep, compared with 16 minutes for the healthy controls, and they slept for 89% of the time they were in bed, which was similar to the amount of time the controls spent asleep.

“What this tells us about insomnia is that there are many ways to intervene,” says James Wyatt, director of the sleep disorders center at Rush University Medical Center and a spokesperson for the APSS. “We have in our armamentarium a variety of medications and cognitive behavioral treatments, but this opens the door to an entirely new third category of mechanism device treatments.”

Cooling off the brain makes sense, since melatonin, one of the more effective medications to help people sleep, also works in part by lowering body temperature.

More studies will have to confirm the results, and it’s not clear yet which patients may benefit the most from the cap, but for those who are uncomfortable with taking medication, or for whom existing treatments may not work, the cooling strategy may be helpful. In the study, those whose caps were set to the lowest temperatures were able to get more sleep than those whose caps were slightly warmer. Falling asleep, it seems, may simply be a matter of cooling off.