London: Some people can sleep through anything because their brains are capable of "fending off" noise.
Researchers have found that heavy sleepers are able to block outside noise getting to their brains and lead to undisturbed sleep.
The discovery of the system, which only works at night and is equivalent to shutting your eyes, could lead to the development of "chemical" earplugs - drugs that block out noise during sleep, says a Telegraph report.
Researchers analysing brainwaves found that the mind produces pulses called "spindles" during sleep - which seem to protect the consciousness from noise, reports the journal Current Biology.
People who produce more spindles are less likely to wake up when exposed to any form of noise, the study found
Jeffrey Ellenbogen, assistant professor of Neurology at the Harvard Medical School, said: "Noise-induced sleep disruption is one of the most common complaints that people have for why they have difficulty sleeping."