We’re aware of the impact of our environment on our sleep, but we rarely think about whether our five senses remain perceptive and active when we sleep, and if so, how this awareness manifests itself while we’re sleeping. Even though it’s not immediately obvious, outside stimuli can have a great impact on our sleep and what happens during it.
Some of our senses protect us from such stimuli affecting our sleep, which is the case of our sense of sight, while others simply process this information and manifest it in our dreams, which is the case of our sense of smell. Regardless of where your curiosities lie, if you’ve ever asked yourself: “which of our five senses are still active when we sleep?”, then our article will be of great help.
We will provide a general overview of how each of our senses affects our sleep and go over some of the processes that occur while we’re sleeping. Additionally, we included a section where we go over some of the ways sleep deprivation could negatively affect our senses, as well as an FAQ section.
Without further ado, let’s first see why our senses work while we sleep.
Why Do Our Senses Work While We Sleep?
You wouldn’t be surprised to know that our senses are still at work even while we sleep. Our bodies are complex machines, so the activity of our senses is indicative of how our body is trying to preserve our safety even while we sleep. It makes sense from an evolutionary standpoint since many predators lurked in the dark and our ancestors had to stay alert to save their lives.
Many of us experience dreams that are a result of some kind of stimulation of our senses. For instance, if someone in the house is baking bread, we might have a dream that involves bread, pastries, or a bakery. Not to mention, some of our senses are extremely sensitive while we sleep and any stimulation might lead to us waking up, like, for example, if our eyes are exposed to direct sunlight or harsh lights.
With that out of the way, it’s time to go over each of the senses and see how they remain active while we’re asleep.
What Happens to Our Sense of Sight While We Sleep?
Most of us have noticed at least one phenomenon that occurs to our sense of sight while we sleep. If you’ve ever observed a person who’s sleeping, you might have noticed that their eyes move around if they’re dreaming. But this is not the only sight-related change that occurs while we dose off. In this section, we will explore what happens to our eyes while we sleep during the five stages of sleep.
As we mentioned earlier, our eyes remain receptive to harsh outside stimuli even while we sleep, so they continue to work while closed. Whether it’s natural lighting or artificial light, if you’re a light sleeper, chances are these changes will result in your sleep being disturbed. But the function of our eyelids isn’t only to protect us from direct light while we sleep, they also serve to keep our eyes moisturised and prevent them from drying out.
As you might know already, we go through five stages of sleep in total – four non-REM stages of sleep and REM (rapid eye movement) sleep. We undergo these stages of sleep a couple of times per night, with the REM stage gradually increasing in duration.
During the first stage of non-REM sleep, when we’re slowly shifting from being awake to being asleep, our eyes roll slowly, and they might even start to open and close a couple of times. However, once this first stage passes and we enter the second stage of non-REM sleep, our eyes remain completely still until we enter the final stage of sleep – REM sleep.
During REM sleep, we experience deep and restorative sleep. It’s also been established that this is the stage where we dream, so our eyes move fast and the part of our brain that’s responsible for processing visual information remains active. Even though that’s its task during the day, at night this part of our brain has a different function – that of filtering out all the information we gathered during the day and forming memories from the information it deems worthy of keeping.
Another interesting fact worth mentioning regarding sleep and sight is that it usually takes anywhere between 20 to 30 seconds for our eyes to send a signal to our brain once we wake up, which explains why we can’t make sense of what we see immediately after we wake up.
In short, our eyes either remain still or move around during the night, depending on whether we’re going through non-REM sleep or REM sleep. We sleep with our eyes closed in order to prevent light from disturbing our sleep, as well as keep our eyes moisturised. With that said, some people do sleep with their eyes open and this condition is called nocturnal lagophthalmos, which can occur from sustaining injuries or damage to the facial nerves or eyelids. A lack of sleep manifests itself in our eyes as well, causing them to become itchy and dry, so it’s crucial that we get enough sleep every day.
What Happens to Our Sense of Smell While We Sleep?
The effect of sleep on our sense of sight is commonly observed, but not many people make the connection between our sense of smell and sleep. Even though we might struggle to see how our sense of smell could impact sleep, it’s more than apparent that smell has a direct impact on sleep.
One of the ways we can observe how our sense of smell impacts sleep is by looking at the effect of aromatherapy on our sleep. It’s clear that certain scents can help us get better sleep and even influence the trajectory of our dreams, which is the case with the example of smelling bread that we gave you earlier.
It won’t come as a surprise to learn that some smells can help us get better sleep. By exposing our nostrils to some scents before going to bed, we can increase our chances of falling asleep faster and getting into a relaxed state more easily. Aromatherapy works by making our bed and our sleeping environment more appealing, so we are more likely to want to go to bed earlier and relax once we get there. Essential oils are a great tool of aromatherapy you can use if your goal is to create a more inviting sleeping environment.
There aren’t clear guidelines in terms of what scents you need to use in order for aromatherapy to work on you, as it largely depends on your personal preferences and the kind of scents you find relaxing. With that said, lavender has been shown to put us in a relaxed state of mind and is associated with improved sleep quality. Another essential oil that has shown very promising results is camomile, which helps by making us fall asleep faster and improving our overall sleep quality.
You could also use essential oils for the opposite effect. If you have a hard time waking up in the morning, why not try using aromatherapy in conjunction with your morning tea or coffee ad notice if you see any improvements?
Sense of Taste
Unsurprisingly, our sense of taste is the one that remains inactive while we sleep. This makes sense since we need to be chewing on food or drinking liquids in order for our taste buds to activate, which, of course, doesn’t happen when we sleep.
Our sense of taste is, however, connected to our bedtime routine, and there are some things you can do to ensure that you remain as relaxed and ready for bed as possible. One common remedy that’s used to heal sleeplessness is lemon balm tea. Drinking a cup of lemon balm tea two hours before you go to bed can make you fall asleep faster and even lead to better sleep quality. Since it’s easily accessible and relatively inexpensive, you can easily try it next time you feel like you can’t go to bed.
Chamomile tea also helps us get better sleep since it’s shown to have a mild sedative effect on our bodies. Apart from that, it’s an excellent choice if you struggle with anxiety at night, or if you simply find it hard to relax before going to bed.
How Our Sense of Touch Impacts Sleep
Unlike our sense of taste, our sense of touch is heavily impacted by sleep and remains active during the different stages of sleep. If you’re a light sleeper, chances are you will get woken up if someone touches you while you sleep or if you accidentally hit your foot on the bed.
Despite the obvious ways your sense of touch can respond to different stimuli while you sleep, it can also make it a lot harder for you to fall asleep. To keep your sense of touch pleased, you will have to keep a few things in mind to ensure that you go to sleep as soon as possible. This is especially important if you’re someone who finds it hard to fall asleep or suffers from insomnia.
First things first, pay attention to the type of mattress you purchase. You need a mattress that’s sufficiently comfortable for your body type and favourite sleeping position, and one that results in optimal temperature regulation so that you don’t get disturbed by night sweats or chills in the middle of the night.
If you’re sleeping with a partner or a pet, your sense of touch will naturally be more active. While it will result in a boost of positive hormones and make you feel good initially, there are some drawbacks you should be wary of. If they shift around a lot as you sleep, your sleep can be disturbed and interrupted, especially if you’re a light sleeper. If this is a common occurrence, consider investing in a mattress that has great motion isolation properties.
Does Our Sense of Sound Work While We Sleep?
Many of us are exposed to different types of sounds before and after going to sleep, such as traffic if we live in the city. Sometimes, we do it consciously by putting on a movie or our favourite show in the background while we doze off. This begs the question: is our sense of sound still active while we sleep? Can we hear the same things we hear while we’re awake? How does our brain process the sounds it hears while we’re sleeping?
When we are exposed to different sounds at night, our brain processes these noises all at once, however, eventually it chooses one voice or sound to focus on. The same thing occurs when we’re attending a party and trying to have a conversation with someone, all the while drowning out all the noise in the background. This is proof that our sense of sound does in fact function while we sleep and it consciously decides to focus on certain voices over others. The brain filters out sounds based on importance – for example, it’s extremely wary of the sound of our alarm clocks but it would easily dismiss the barks of the neighbour’s dog, deeming them unimportant. Scientists aren’t sure why this occurs, but it still remains a fascinating phenomenon to research.
Unlike our eyes which are most active during the REM stage of sleep, our sense of sound remains active during most stages of sleep. What these two senses have in common, however, is that the external stimuli they experience have the ability to affect our dreams. In this instance, if we listen to a particular sound or if a loved one is talking in the background while we sleep, there is a chance that that particular sound or the voice of our loved one will show up in our dreams. A common occurrence people report is the integration of their alarm clock sound in their dreams.
Just like dreams, we don’t remember the sounds we hear while we’re sleeping even though our brain processes them as they occur throughout the night.
How Does a Lack of Sleep Affect Our Senses?
We went over all the senses and discussed how they can affect sleep, but what about the effect of sleep (and lack thereof) on our senses? In this section, we will take a look at how our senses are affected when we fail to get sufficient sleep.
One of the best examples that demonstrate how a lack of sleep affects our senses is vision impairment. Whether you intend to drive a car or do some bedtime reading, this is a serious side-effect that can be potentially life-threatening. Our vision becomes impaired due to a lack of sleep because our brains fail to process the necessary information on time and to the necessary capacity. This will hardly come as a surprise to any of us since we’ve all experienced difficulty in problem-solving when we don’t get enough sleep and how our brain seems to slow down when that occurs.
Apart from your vision, your sense of sound may also be impaired when you’re in a state of sleep deprivation. You might notice that it takes a longer time for your brain to process the sounds it hears. The impact on the other senses isn’t as strong, however, sleep deprivation comes with a whole host of negative side effects that are detrimental to your health in the long run, so we recommend doing the best you can to get at least seven hours of sleep at night.
Which Senses Are Still Active During Sleep?
The senses which remain active while we sleep are our sense of sight, sound, and touch, while our sense of taste and smell remain passive.
Which Senses Wake Up First?
If you’re curious about which of our five senses is still active when we sleep, then you also might be wondering about which of our senses wakes up first. One of the first senses that wakes up is our sense of sight – it takes approximately 30 seconds for our eyes to send a signal to our brain once we wake up. Our sense of smell is also quick to activate once we wake up.
Can You Smell in your Dreams?
While scents can impact our dreams, our sense of smell doesn’t remain active while we sleep, especially during the deep stages of sleep such as the REM stage.
We hope you enjoyed our article on how the five senses affect our sleep!
Most of our senses remain active while we sleep, which is a result of the different types of stimuli we are exposed to while we sleep. Some stimuli awake our senses, while others have the power to influence the trajectory of our dreams.
Our sense of sight remains active even while we sleep because our eyes move around when we dream and the part of our brain responsible for processing visual information works hard at creating new memories. Our senses of smell and taste remain mostly passive, while our sense of sound remains active depending on what kind of sounds we hear during the night. When it comes to our sense of touch, it’s greatly affected by whether we’re sleeping with a partner or a pet. If that’s the case, think about investing in a mattress that has good motion isolation so that your sleep remains undisturbed.
A lack of sleep can be detrimental for our senses since our brain fails to process information at a regular pace and to the normal extent. It’s important to get at least seven hours of sleep for optimal health and longevity.