PROVIDENCE, R.I., May 17 (UPI) -- Rhode Island researchers have found smells cannot disrupt sleep, said a study published in the latest issue of the journal Sleep.
Study participants easily detected odors when awake and in the early transition into sleep, but once asleep they did not detect odors at all.
"Human olfaction appears insufficiently sensitive and reliable to act as a sentinel system," said Rachel S. Herz, visiting assistant professor of psychology at Brown University.
Herz and her colleagues studied the effects of two scents -- the pleasurable peppermint and offensive pyridine -- on six participants in their early 20s.
Over two nights, participants wore elastic chinstraps to encourage nose breathing. Researchers presented odors through a tube attached to an air-dilution device. The odors were tested during various phases of sleep, from light sleep to deep sleep.
No one responded to peppermint during sleep, at any stage of sleep. Responses to the intense and noxious pyridine were infrequent and did not wake any participants in the deepest stage of sleep.
