How Does the Sense of Smell Work? Things You Should Know Update 06/2024

Few people consider smell while contemplating sleep and the connection between the senses. Because of the obvious ways in which light, loudness, and comfort can effect sleep, the senses of sight, hearing, and touch are often given more attention.

A person’s sense of smell can have a direct impact on their ability to fall asleep. Smell and sleep have a complex relationship, despite the fact that odors don’t normally prompt a person to get out of bed.

Aromatherapy with various scents may help you sleep better, wake you up in the morning, or even impact your dreams and memory formation while you’re sleeping. In addition to regulating your sleep, circadian rhythms also influence your sense of smell.

Research into the link between smell and sleep is ongoing, but knowing what has been revealed so far might help you create a better sleep environment in your bedroom.

How Does the Sense of Smell Work?

Olfactory systems are complex, and your sense of smell is no exception. A wide variety of substances in our surroundings are detected by olfactory neurons, special cells in the nose. In order to identify a smell, these neurons are directly linked to the brain, making it possible to identify which neurons are triggered by the smell.

Taste and smell are intertwined in part because scents can reach neurons via the nose or the back of the throat. The common chemical sense, which aids in the detection of irritating substances, can also be aided by nerve endings in other places of the body.
Making Sense of Scents: Smell and the Brain

Can Certain Smells Help With Sleep?

Certain scents may help you sleep better because of the importance we place on our sense of smell. Aromas that induce a sense of calm before bedtime can help you get a good night’s sleep and feel rested the next day.

Psychological and physiological responses can be elicited by odors in addition to their detection and identification. Depending on your mood, your sense of smell can either put you at ease or make you queasy, depending on how strong the scent is. Smells can become a part of your emotional memory, causing you to react in the same way every time you smell them.

It isn’t surprising that certain aromas are associated with a more welcoming bedroom atmosphere. 78% of respondents to the National Sleep Foundation’s 2012 Bedroom Poll said they were more eager to get into bed when their sheets were fresh, and 71% said they slept better when their sheets were fresh.

Although sheets are one source of bedtime smells, there are suggestions that aromatherapy may encourage better sleep by bringing additional scents into the bedroom.


Scents from plants are used in aromatherapy, an attempt to improve many aspects of health. Aromatherapy is focused on the use of essential oils, which are liquids derived from plant materials such as flowers or herbs and date all the way back to ancient Egypt.

Essential Oils

Essential oils can be utilized in aromatherapy in three primary ways.

  • The oil is dispersed and mixed with the air in a space using the indirect inhalation method, resulting in low quantities of aroma in each breath. Diffusers and absorbent materials such as tissues can be used to disperse the oil.
  • Using the direct inhalation approach, a higher concentration of essential oil constituents can be inhaled. Most people use hot water and drops of essential oil to inhale the vapor at home, rather than using specific nasal equipment in clinical investigations.
  • The carrier oil, which is a less potent oil, is used to dilute the essential oil before it is applied to the skin via rubbing or massaging. As a result, both the nose and skin’s olfactory receptors can detect the scent. These receptors may provide an additional input to the body’s sensory system, despite the fact that much more research is needed.

Can Aromatherapy Help With Sleep?

Aromatherapy has been shown to improve sleep quality by generating a relaxing and restful environment in the bedroom.

When it comes to getting ready for bedtime and throughout the night, aromas that are associated with feelings of serenity and relaxation may be beneficial. Insomnia and other sleep disorders are typically exacerbated by mental hyperarousal, such as stress and anxiety.

Certain essential oils may help alleviate this problem by generating a sense of well-being. A analysis of published scientific research indicated that the majority of studies concluded that essential oils can help people sleep better. It was shown that patients with post-traumatic stress disorder (PTSD), a condition characterised by nightmares and major sleep issues, were more likely to sleep well when exposed to pleasant fragrances while in bed.

Insomnia and other sleep disorders are common, but there isn’t enough scientific evidence to recommend aromatherapy as a conventional treatment for them. Aromatherapy research has a number of difficulties, some of which are listed below:

  • Since it’s so easy to pick up on a scent, it’s impossible to run a randomized, blinded study using a placebo.
  • Many current aromatherapy studies use a hose or nasal applicator to administer smells directly to the nose during sleep. It’s not clear if other aromatherapy approaches, like as indirect inhalation, have the same positive effects, even if recent studies demonstrate that they do.
  • Researchers may employ essential oils that have different chemical compositions from those that are available to the general public in their investigations.

Are There Side Effects to Aromatherapy?

Aromatherapy has been shown in most studies to have little or no negative effects, and essential oils are generally regarded safe when used according to directions.

Certain essential oils, particularly when administered topically, might cause allergic responses in some persons. When exposed to the sun’s ultraviolet radiation, the skin’s sensitivity may be increased, especially when using citrus-based or other types of essential oils.

Several compounds identified in tea tree and lavender essential oils have been determined to be potential endocrine disruptors, which is to say that they interfere with the production of a variety of gynecological hormones. Rare incidences of prepubescent breast growth in women and aberrant breast development in boys have been related to these oils, according to research. At least 65 different essential oils include the chemicals suspected of causing endocrine disruption. Essential oils may cause endocrine disruption, but further research is needed to determine whether this is possible and, if so, how it may be mitigated.

What Are the Best Scents for Sleep?

For sleep, there appears to be no consensus on the optimal types of aromatherapy. Whether or whether a certain remedy is effective for a given person may be influenced by the nature of their sleep issues and their personal taste in fragrances.

These sections detail essential oils that have been demonstrated to improve sleep, although it is important to realize that much of this research is preliminary or undertaken in specific patient populations that may not be applicable to the general population.

Aromatherapy should not be used as a substitute for other treatments for insomnia or sleep disorders unless specifically prescribed by a doctor.
10 Incredible Facts About Your Sense of Smell | Everyday Health


Lavender is one of the most researched essential oils in the world. Lavender has been linked to better sleep in a number of studies, including those involving persons who suffer from sleep disorders. Heart rate and blood pressure can be reduced by the aroma of lavender. Studies show that persons who ingest lavender before bedtime are more likely to wake up feeling rested.


Rose essential oils have showed promise as sleep aids due to their enticing perfume. Despite the lack of clear evidence, a study of sad patients found that inhaling rose-scented air as they slept improved their mood and sleep.

Aromatherapy using the smells of the damask rose (rosa damascene) was found to significantly improve sleep quality in a hospital coronary care unit research.

Roman Chamomile

Roman chamomile essential oil, when applied to pillows, increased the amount of time older persons spent sleeping in managed care facilities. Anxiety was lowered in cancer patients who had massages using a carrier oil infused with Roman chamomile essential oil, according to a separate study.


As a result of using jasmine essential oil in the bedroom while sleeping, it was found that the amount of time a person spent in bed was increased.

Cedar Extract

An experiment including the aroma of cedar extract helped persons napping during the afternoon fall asleep faster despite the fact that it was not as thoroughly investigated.


Those who inhaled cannabis essential oil derived from plants lacking the psychoactive ingredient THC, found it to be more calming, according to a pilot study.


An essential oil that comes from the Cananga tree, ylang-ylang can help quiet the mind and decrease the heart rate, making it ideal for use prior to bedtime.

What Are the Best Scents To Wake You Up?

Just as with sleep-inducing aromatherapy, there isn’t a perfume that will work for everyone. However, research has identified a few scents that might.


But not everyone like the taste of coffee or is willing to take in the stimulant caffeine. A study discovered that merely smelling coffee boosted alertness, attention, and memory without the physical effects of caffeine; this is another possibility.


Essential oil of rosemary has been discovered to stimulate the brain and may improve overall cognitive function.


In several studies, peppermint essential oil has been shown to improve memory recall and increase sensations of alertness.


Sage (Salvia officinalis) and Spanish sage (Salvia lavandulifolia) essential oils have been linked to improved mental performance in preliminary studies.

Blended Oils

Blends of essential oils have been shown to improve concentration and attention span in studies. Cognitive function and focus were increased in one study using an oil mix including the key chemical components 1,8-cineole, 3-carene, -pinene and -caryophyllene

How Does Sleep Affect Your Sense of Smell?

A congested nose will tell you that our sense of smell isn’t always the same strength. Your circadian rhythm is one of the factors that affect your olfactory system. In addition to promoting sleep and wakefulness, this element of our biological clock influences a wide range of other physical functions.

When it comes to smelling, our circadian rhythms have a direct effect on how sensitive we are to the scents around us. Nighttime and early morning smells are often lightest, with peak levels occurring around nine in the evening (PST). This decrease in sensitivity to smells during the night could explain why fragrances rarely induce people to awaken from their slumber.

Can Smells Affect Dreams?

Smells have been shown to influence dreams, but the exact nature of this effect is yet unknown. In one study, nice smells elicited more positive dreams, while unpleasant smells elicited more negative ones. Other studies, on the other hand, indicated that people’s unpleasant dreams were exacerbated when they were exposed to a familiar smell or a favorite aroma.

It’s not yet apparent if and how aromatherapy can influence dreams, and further research is needed before this is known.

Can Smell During Sleep Improve Memory?

Sleep is a vital element of the learning process since it helps to strengthen the memories that are already there. Smell exposure in the bedroom has been studied by sleep experts as a way of bolstering this process of memory consolidation.

This learning method makes use of scents as a memory trigger. A person is awake and learns new knowledge when they are exposed to a specific aroma to achieve this effect. During the night, they are exposed to the same scent. This odor-based cueing boosted memory recall on a vocabulary test in a study of schoolchildren. Exposure to the same odor the following day during testing may also provide further benefits.

The hard effort of learning new material isn’t eliminated, but students and others who want to increase their odds of establishing useable memory while they sleep may profit from this strategy.

Can Smell Help You Feel More Awake in the Morning?

Many individuals are interested in aromatherapy as a sleep aid, while others want to learn how to use odors to wake up feeling more alert.

Aromatherapy can’t make up for a lack of sleep, but it can help you get a good night’s rest. However, some scents can help you wake up more alert and energized, as well as throughout the day.
How do we smell things? - Queensland Brain Institute - University of Queensland

A history of smelling 

One of the most basic functions of the human body, according to biologists, is the brain’s ability to process smell. Early Man’s capacity to detect and respond to odors was critical to survival. Is there a stench of burning? You’re on the move. Rain is in the air, right? You’re looking for a place to hide. The limbic system, one of the brain’s earliest regions, is intimately connected to the scent cells in our noses. Emotions, behavior, and long-term memory are all controlled by the limbic system.

Smell influences everything in our lives, from our hopes and aspirations to our financial decisions, as study has long demonstrated.

Researchers observed that the quantity of money bet practically doubled when attractive scents were used to enliven the gaming area.

Our bodies respond to various scents in a specific way. So, what can we do to make better use of our sense of smell to help us sleep better?

Smell and sleep – a not so unusual friendship

At the Sleep Disorders Center of Heidelberg University, participants had the option of experiencing either:

  • The delightful aroma of flowers.
  • The foul odor of hydrogen sulfide.
  • There was absolutely no odor.

Findings revealed a strong correlation between participants’ vivid dreams and the smell they had been exposed to. Those who were exposed to a nice smell had positive dreams, whereas those who were exposed to the smell of sulfur had negative dreams or even nightmares. The findings were so conclusive that researchers decided to look into the connection between unpleasant odors and nightmares.

We may conclude from this and other studies that smell has a significant impact on sleep. Why? It’s because our sense of smell is controlled by the same area of our brain that governs our sleeping patterns.

Which scents, on the other hand, have a calming effect on sleep?

These scents can help you sleep better

  • It’s true that the aroma of coffee can help you get to sleep. It may have a relaxing impact, according to UCLA experts.
  • The scent of roses has been shown to reduce blood pressure and the number of breaths taken per minute, making it simpler to drift off to sleep. If you’re looking for an easy way to incorporate rose into your night routine, you’re in luck!
  • Smell of lavender has been shown to reduce anxiety, stress levels, pain, and more by calming the heart rate.
  • Geranium has a calming, mood-lifting scent that is frequently referred to as a natural antidepressant. How often do you find yourself unable to sleep due of anxiety or fear? Geranium is a wonderful sleep aid since it helps you relax and drift off to sleep more peacefully.
  • In terms of its influence on sleep, clary sage differs from normal sage in that it is regarded to be more relaxing. Menopausal women may also benefit from clary sage’s antidepressant properties, according to a study. If you’re searching for a more earthy aroma, this is an excellent choice.
  • Sweet marjoram, which was formerly a favorite of the upper-class, is still one of the most pleasant and refined scents. When it comes to sleeplessness, sweet marjoram is a good choice because of its relaxing properties.
  • Jasmine: If you’ve ever had a cup of tea, you’ve probably smelled jasmine. Having a pleasant aroma, jasmine has been shown to lower stress and improve sleep quality. If you appreciate the scent of jasmine, a simple addition to your nightstand is all you need.

From peppermint and chamomile to stop snoring and olive oil to help with sleep apnea, the list of sleep-enhancing smells goes on. However, another fascinating result is that if you locate a pleasant aroma, it is likely to help you sleep better.

Lavender aromatherapy, according to University of Maryland researchers, may help people with sleep difficulties relax, sleep better, and feel better by slowing their nervous system’s activity.

How to introduce scents to your bedtime routine 

Even if you don’t have a lot of money to spend, there are a lot of products out there that can help you include scents into your nighttime rituals.

In most stores, lavender and jasmine may be purchased as plants and are easy, light-scented additions to your nightstand or window sill.

Put some coffee in a bowl next to your bed and see if it impacts your sleep. You definitely drink coffee at home.

Popular essential oils include marjoram, geranium, and clary sage. Before you go to bed, experiment with their effects by placing them in an aroma diffuser or a small bowl of water, or by dabbing them lightly on your skin (on the wrist and neck). Is the odor too strong? Before going to bed, try adding a few drops of essential oil to a warm bath.

Many air and fabric fresheners and candles are scented with rose, which is a popular aroma. One of them might help you get some shut-eye.

Pillow spray, for example, is a product developed to maximize the influence of aroma on sleep. Ultimately, it’s up to you.

Ready to discover which scents soothe you and allow you to sleep soundly?

And how to use aromatherapy to revive OR relax you

If you’re looking for ways to enhance your productivity, reinvigorate your energy, or help you sleep, aromatherapy may not be the first thing that springs to mind. It is widely accepted that our sense of smell is our most powerful and impactful sense. The sense of smell is ten times more accurate than the sense of taste, according to new research.

In your brain, a pea-sized cluster of scent receptors is activated when you inhale something. Scent is sorted and your limbic system is activated, which is responsible for regulating basic human activities (such as learning and emotions). Is there a particular scent that brings back memories for you? You can now understand why. Taking a whiff of a perfume activates the immune system, lowers blood pressure, and stimulates the digestive system.

Sniffing your way to better health, better sleep, or increased productivity is a real possibility.

Swapping pills for scents

Imagine being able to heal yourself without ever needing to take a medicine. Exposure to various fragrances has been shown in numerous studies to safeguard health over the long term, as well as to alleviate symptoms of stress and pain, nausea, and sleeplessness. Aromatherapy has even been shown to destroy virus, E. coli, and cancer cells when used in combination with fragrances and essential oils..

Between 2005 and 2010, a report from the Substance Abuse and Mental Health Services Administration revealed that the number of persons taking Ambien for sleep-related difficulties and ending up in hospital emergency rooms climbed by approximately 220 per cent. We can’t help but wonder whether a little aromatherapy would make things a lot more peaceful in the ER.

It’s a tough question. Aromatherapy is an unregulated industry, and more research is needed into its possible adverse effects. In the case of essential oils, there is some evidence that while moderate exposure can be beneficial to the heart, chronic exposure can increase the risk of cardiovascular disease.

Experts recommend limiting your exposure to no more than an hour a day and adhering to the bottle’s directions. If you take medication on a daily basis or have a long-term health condition, it’s a good idea to tell your doctor. Exercise caution and keep track of your development as you would with any medication.

Ready to sniff your way a healthier night’s sleep?

Using a diffuser (which may cost anywhere from $25 to $200) is the most efficient way to disperse essential oils into the air, but a bowl of hot, steaming water can also be used to do the trick. Drop a few drops of essential oil onto a cotton ball and inhale normally for one to two minutes while driving or at work.

Check out our top aromatherapy scents if you’re interested in giving it a whirl.

  • It has also been used to treat depression, anxiety, insomnia, and migraines, in addition to its traditional uses as a sleep aid and digestif. Before you go to sleep, sprinkle a little water on your pillowcase.
  • Citrus fruits like oranges and lemons are known to help people feel more at ease and happier. While getting ready for work in the morning, add a few drops of orange or lemon essential oil to your diffuser (or a bowl of steaming water). What a shift in perspective.
  • Peppermint lowers fatigue by lowering cortisol levels (the stress hormone). Because of this, it has been demonstrated to lessen sugar cravings as an additional benefit. Mid-afternoon, try a cup of peppermint tea rather than a cup of coffee, which may keep you up and disrupt your sleep.
  • Rosemary boosts brain strength, allowing you to do more complex mental tasks more quickly and accurately.
  • It has been shown to increase stamina and stave off weariness in studies. Take some rosemary to work with you, and you’ll never be without it.
  • Studies have found that sage not only improves memory and attention, but it can help lower blood pressure.
  • Hang a few sprigs in your kitchen to help you relax during the frantic minutes leading up to dinner.
  • For generations, people have used chamomile as a light sleep aid to alleviate insomnia. Apply some chamomile oil to a cotton ball and place it near your pillow to help you sleep better at night.
  • In addition to calming the mind, Jasmine has also been shown to increase energy levels. Stress and anxiety can be alleviated by drinking jasmine tea. Headaches can be relieved using a compress infused with jasmine petals.
  • Bergamot has sedative, stimulant, and anti-inflammatory properties. Use it as a tea to calm an upset stomach and unwind your body before going to bed at night.
  • Rosa can be used as a skin tonic and mood enhancer when applied topically.

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