How Your Five Senses Influence Your Sleep
Updated: Aug 1, 2018
Welcome to the beginning of a series of posts on how each of your five senses affect your quality of sleep. I look into whether our senses are altered when we are asleep, and examine each sense individually to determine how exactly they influence our nightly slumber.
Our sleep quality and how to improve it has become a hot topic in recent years. It's little surprise since we spend about one-third of our lives asleep. Sleep scientists have consistently proved that regular limited or poor quality sleep significantly impairs our cognitive and physical abilities. The message out there according to the NHS is that long-term sleep deprivation can put you at risk of medical conditions such as obesity, heart disease and diabetes as well as decrease your life expectancy.
As a sensitive person, I personally have history of not being able to sleep as well as I would like. Over the years this has led me to extensively research how sleep affects the body and what conditions create a more ideal sleep environment. Through experimentation based on findings from scientific studies I have come to a profound set of conclusions: Firstly, sleep doesn't just happen. Just like anything else we want to do well, it requires a little dedication to find what works for us individually. Secondly, it's very much about what has gone before. Getting into good habits in the hour or so leading up to bedtime will almost certainly result in better sleep.
Since it was largely my acutely honed senses that made getting a good nights slumber a multi-sensory balancing act, this was where I begun my investigation into a better night's sleep.
How our senses affect our sleep
From my experience, certain senses such as touch provide a more effective sensory input to disrupt sleep then the others - since shaking is the most well-known way to wake someone. Hearing also seems moderately unaffected by sleep as most, if not all, alarm clocks, rely on this sense. So what specifically is controlling our sensitivity and our responses to certain stimuli over others? Which sensory inputs have the ability to disrupt our sleep the most?
Lets begin by exploring how our brain activity is altered whilst we're asleep. During sleep, as our body activity decreases, our senses continue to function. Whilst our senses become 'dimmed' due to our obvious state of unconsciousness, there is actually no effective way to turn them off completely.
What does alter however, is our cognitive processing of changes in sensation. Simply put, our higher brain functions allow us to 'ignore' certain sensory input. When the body is awake, it is the parietal lobe (relayed through the thalamus) which receives the sensory information from all over the body and responds to it. In order to sleep your brain must weaken these receptors significantly, though not enough that should we hear something too loud or unfamiliar we are unable to respond. This is where the boundaries between resting and wakefulness overlap. By morning the amount of stimuli needed to overcome the altered processing of our senses is diminished, allowing something such as the sun shining in through the curtains to wake us up.
Just how un-reactive we are to external stimuli whilst we sleep depends a lot on the person, their age, lifestyle factors and phase of sleep. Studying the senses whilst we sleep has always presented a challenge for scientists. After all, what type of subject could naturally get a 'normal' night's sleep in a laboratory bed with electrodes glued to their heads? I would certainly find the process so disconcerting and sensorially stimulating, I wouldn't get any sleep!
In the following posts on 'sleep and the senses', I explore each of the five senses in depth, as well as provides a few handy suggestions how soothe overactive senses in preparation for a good night's sleep:
Sight and Sleep: How Light Levels Impact Our Sleep Quality.
Taste and Sleep: Can Certain Tastes Impact Our Sleep?