By Brandon Peters, MD
In preparing the guest bed earlier this evening, a lavender spray we had purchased in the San Juan Islands was sprayed between the sheets. It smelled nice enough, but I wondered: Can scents like lavender actually promote sleep? Beyond anecdotal evidence and a positive association, is there any proof that aromatherapy does any good to ease insomnia? I decided to dig into the idea, a process that can reveal how I generally approach sleep science with both an open mind and a healthy dose of skepticism.
From Lavender Sprays to PubMed
What is the best way to investigate a question? Many people may fire up their computer or smartphone, hop on their preferred browser, and seek an answer from a reputable source. No doubt this leads millions of people each year to read what I have written on sleep. But how do I find answers when I need guidance?
I may begin an investigation by reviewing textbooks, perusing academic journals, or conferring with experienced colleagues. In many cases, I search the best information from a database that summarizes the abstracts of scientific and medical literature that extends back decades. I usually start by searching PubMed, a service of the U.S. National Library of Medicine and the National Institutes of Health.
To investigate the sleep-promoting effects of lavender, I performed an advanced search with only two search terms: “sleep” and “scent.” This results in the presentation of 129 articles, dating back to 1966. (Incidentally, I also reviewed “sleep” and “lavender” and the 76 articles, some of which overlapped.) Some of these articles were irrelevant, presented no information beyond the citation, or were in foreign languages. This narrowed the relevant content and allowed me to focus my reading.
Sleep Research Can Be a Shallow Pool
One thing I have learned over the years is that the depth of research on various topics within sleep medicine may be disappointingly shallow. The topic may not be well-studied, and often the research that is available may be based on very small populations. For example, most research on the effects of lavender on sleep has been done on groups of fewer than 100 people.
The outcomes measured may be overly subjective, imprecise, or non-generalizable. A blunt tool may lead to a lack of perceived benefit from an intervention. Moreover, if the soporific effects of lavender is studied in a small group of male college students with no medical problems, how much does the result apply to an elderly woman who has advanced cancer and chronic pain?
Finally, the gold-standard of medical research (a randomized controlled clinical trial) is frequently absent. The funding for such investigations may never exist.
As a result, informed decisions and evidence-based recommendations are often made based on the imperfect research that exists.
Does the Nose Take a Nap?
Based on the research that exists, there are a few interesting findings:
Pleasing smells (including lavender) may reduce anxiety and promote sleep onset by enhancing slow-wave sleep oscillations.
Some scents reduce the time it takes to fall asleep and may even increase total sleep time (such as valerian).
Introduced smells seem to have little ability to rouse the sleeping brain, and smells may never wake someone as effectively as an alarm clock, but strong smells (like lemon) may make it hard to fall asleep.
Exhalation may become prolonged in the presence of specific odorants, and this could have an intriguing influence on sleep apnea.
Smell is strongly associated with memory formation, and this may extend into subconsciously enhancing memory consolidation during sleep.
Small research trials suggest a benefit from lavender to enhance sleep, even among chronically ill, hospitalized, and critically ill populations.
Sustained response and benefit from aromatherapy may be elusive, so it is hard to know how much it may improve long-term difficulty sleeping.
What to Do with Lavender?
Based on the existing research, I think the jury is still out on the benefits of aromatherapy as a way to promote sleep. If a scent has a positive association, and is integrated into a regular bedtime routine, it may have a role to ease anxiety and help the transition to sleep.
As the cost of lavender is fairly low, and the risk and harm associated with its use is virtually absent, it may be worth integrating into your nighttime ritual. Further studies may elucidate who may most benefit from the use of specific scents to ease insomnia, and if you struggle, consider participation in a cognitive behavioral therapy for insomnia (CBTI) program.
In the interim, beyond the existing research it may be just as important to contemplate the positive association you may have, so what do you think: Does lavender help you to sleep?
Brandon Peters, MD, is the writer on sleep for Verywell.com, a neurology-trained sleep medicine specialist at Virginia Mason Medical Center in Seattle, and adjunct lecturer at the Stanford Center for Sleep Sciences and Medicine.
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