The Influence of Odorants on Respiratory Patterns in Sleep

Abstract

To assess the feasibility of using odors as a potential mechanism for treating sleep apnea, we set out to test the hypothesis that odorants delivered during sleep would modify respiratory patterns without inducing arousal or wake in healthy sleepers. We used 2 mildly trigeminal odorants: the pleasant lavender and unpleasant vetiver oil and 2 pure olfactory odorants: the pleasant vanillin and unpleasant ammonium sulfide. During sleep, an olfactometer delivered a transient odorant every 9, 12, or 15 min (randomized), providing 21-37 odorant presentations per night. Each of 36 participants was studied for 1 night and with 1 of the 4 different odorants tested. In addition to standard overnight polysomnography, we employed highly accurate measurements of nasal and oral respiration. Odorants did not increase the frequency of arousals or wake but did influence respiration. Specifically, all 4 odorants transiently decreased inhalation and increased exhalation for up to 6 breaths following odor onset. This effect persisted regardless of odorant valence or stage of sleep. These results suggest that the olfactory system may provide a path to manipulate respiration in sleep.

A Systematic Review of the Effect of Inhaled Essential Oils on Sleep

“…The reference lists of these identified studies and systematic reviews, along with OVID Medline electronic article mappings, yielded eight additional studies meeting the inclusion criteria. A total of 15 human studies on inhaled essential oils and their effect on sleep were found, 5,[36][37][38][39][40][41][42][43][44][45][46][47][48][49] and their methods and results were summarized and compared (Table 1).…”

Olfactory Stimulation During Sleep Can Reactivate Odor-Associated Images

“…Olfactory stimulation during sleep significantly alters breathing patterns (Arzi et al 2010). Arzi et al (2012) paired different tones with different odors to demonstrate that simple condition paradigms using the olfactory sniff response (longer in-breaths while presenting positive odors compared to the inbreaths while presenting negative odors) can be carried out during sleep and that the effects carry over to waking life.…”

To sleep: perchance to learn

“…Nonetheless, evidence of true sleep learning-acquiring new declarative knowledge while sleeping-remains elusive. npg n e w s a n d v i e w s sniff response 13 . When subjects inhale a pleasant odor, the inhalation volume is greater than when they inhale an unpleasant odor 14 , and, although an earlier study by the same group failed to find a difference between pleasant and unpleasant odors during sleep 13 , Arzi et al 2 found significantly larger inhalation volumes after pleasant odors than after unpleasant ones, during both REM and non-REM sleep.…”