“In this clamorous modern world, heavy sleepers have an advantage: They can snooze despite noisy neighbors and car alarms, and they’re capable of conking out on a red-eye flight to awake refreshed and smiling.
But how do these sound sleepers do it? According to a neuroscience study published today in Current Biology, they’re blessed with a type of brain activity that may essentially block out noise.
Sleep researchers from Harvard Medical School performed a slightly torturous experiment on 12 healthy volunteers. On their first night at the sleep lab, the subjects’ brain waves were monitored via electroencephalography (EEG), but they were otherwise left in peace. That night, the researchers measured one particular sleep phenomenon: the brief bursts of high-frequency waves known as “sleep spindles.” On the following two nights, the researchers did their best to replicate a really irritating night’s sleep.
“The volunteers would come in and we’d show them this luxury environment with a queen bed and comfy sheets, but there are these four very large speakers pointed straight at their heads,” said study coauthor Jeffrey Ellenbogen.
The sleepers were then exposed to a steady stream of auditory assaults. Each sound — whether it was a phone ringing, an animated conversation, or a jet engine — would be played quietly at first, and then gradually cranked up until the patients’ brain waves showed a disruption to the sleep pattern. After a few seconds of quiet, the researchers cued up the next sound and the process began again.
The results showed that patients with more frequent sleep spindles were better able to tolerate noise; it took higher-decibel sounds to disrupt their sleep patterns. Ellenbogen says this gives researchers a new predictive power.
“If you know how many spindles a person is producing and compare them to others, you can predict who among them will run into trouble when it comes to blocking sound during sleep,” he said.”
Read more at Wired
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