How Do Neurotransmitters Affect Your Sleep?
First added 11th June 2021
By Sophia Rimmer
6 min read
Your behaviour and sleep are greatly affected by brain chemicals flying around your brain throughout the day. Everything from waking up to falling asleep is influenced by the various neurotransmitters firing through your synapses, and each neurotransmitter has a specific function.
In this guide, we'll be breaking down the complex world of neurochemicals and how they affect your sleep. For those who have no idea what a neurotransmitter is and what they do, continue reading to find out.
What are Neurotransmitters?
Neurotransmitters are essentially tiny chemical messengers that travel around the brain and body via different cells ‐ typically neurons. They travel from one neuron to the other via a process called synaptic transmission.
During the process of synaptic transmission, neurotransmitters will be released from one end of a neuron, travel across what is called the ‘synaptic cleft’, to be absorbed by the neighbouring cell. Depending on the time of day and what you’re doing, different neurotransmitters will be sent/triggered, resulting in a change in behaviour.
The receptors on neurons and neurotransmitters work like a lock and key. Each specific neurotransmitter will only bind to a specific receptor. If the neurotransmitter is able to bind, it will impact the receiving cell, either exciting further transmission or inhibiting it.
As you can see, this is all very scientific and there is a lot to know when it comes to neurotransmitters and synaptic transmission – too much to discuss in one section. If you’d like to read more about neurotransmitters specifically, this article offers a great explanation.
What Neurotransmitters Impact Sleep?
There are several neurotransmitters that affect sleep, and they impact it differently depending on the time of day. Some neurotransmitters affect waking up cycles, whereas others affect sleeping cycles. Each has its own role and causes different reactions.
Here is a quick list of key neurotransmitters which affect how we sleep:
- GABA: An inhibitory neurotransmitter that produces calming effects. It’s commonly related to reducing stress, anxiety, and fear.
- Adenosine: An inhibitory neurotransmitter that reduces arousal and promotes sleep.
- Serotonin: An important neurotransmitter that regulates mood, feelings, and emotion. Serotonin impacts your whole body and enables your cells to communicate.
- Dopamine: A neurotransmitter heavily associated with motivation, arousal, and the reward/reinforcement pathways. It’s commonly associated with high energy and alertness.
- Melatonin: This is produced by your pineal gland at the base of your brain and is associated with your circadian rhythms. It keeps and maintains your internal body clock. And is very sensitive to light.
- Norepinephrine: Relates to increased heart rate and blood pressure and activates the sympathetic nervous system. Many of you will know this as the fight or flight response.
- Acetylcholine: A neurotransmitter that activates the parasympathetic nervous system – reducing heart rate and blood pressure. This has the opposite effect of the sympathetic nervous system previously discussed.
- Orexin: A neuropeptide associated with arousal, wakefulness, and appetite. It is also known as hypocretin.
All these neurochemicals come into play at different times of the day. Some are responsible for waking and others for sleeping. In most cases, they act together to ensure you get a well‐rested night.
Neurotransmitters That Affect Waking
Now you have a grasp of what neurotransmitters are and which are involved in sleep, let’s explore the specific chemicals that trigger waking. These neurotransmitters usually promote arousal and alertness.
The waking process is governed by a region near your brain stem called the ascending reticular activating system (ARAS). This system is inhibited during sleep but begins to activate slowly as you wake up. This process releases several chemicals, such as orexin, adenosine, serotonin, acetylcholine, norepinephrine, and dopamine. Your hypothalamic-pituitary‐adrenal axis (HPA) is also activated here, which is associated with your stress response. But that’s a topic for another time.
Orexin and Sleep
Orexin has the simple job of activating the ARAS previously mentioned. This system promotes the release of the rest of the ‘waking chemicals’. Therefore, orexin essentially kickstarts the entire process.
Orexin is found in cells in a subregion of the hypothalamus – a deeper section of the brain with the role of releasing hormones.
Acetylcholine and Sleep
Acetylcholine helps to wake you up and keep you awake. It does this by promoting “faster brain waves” and helps to support important mental functions, such as attention, memory, and sensory processing.
Serotonin and Sleep
Serotonin is an important neurotransmitter in the body and is responsible for waking you up and keeping you awake. It also has a big impact on your mood and happiness.
The activation of serotonin promotes further activation of other waking‐up processes. It also has a role in temperature regulation, allowing you to cool as you sleep.
Dopamine and Sleep
Dopamine has a small role in the waking process but is still present. It has been linked to the motivation to spring out of bed and seek out rewards and pleasure. View it as the neurotransmitter that makes it bearable to get out of bed when you want to lay in on a Monday morning.
Dopamine helps you to stay alert and helps you maintain an active mind.
Norepinephrine and Waking
Norepinephrine has the role of activating arousal. It gets your brain and body ready for action. This chemical allows you to stay awake and alert throughout the day, greatly contributing to wakefulness.
Neurotransmitters That Affect Sleeping
As well as waking, neurotransmitters also play a significant role in ensuring you fall asleep at an appropriate time. These chemicals build up throughout the day. As you make decisions and experience thoughts and feelings, these chemicals are produced as a by‐product. Once they reach a threshold, you’ll start to feel sleepy.
As your brain starts to “fill up” with these sleep‐promoting chemicals, areas of your brain associated with wakefulness begin to get blocked. Additionally, they will begin to activate regions of the brain associated with sleep, allowing you to drift off naturally.
GABA and Sleep
Gamma‐aminobutyric acid (GABA) is essential for starting the sleeping process. It is a primary chemical responsible for “turning off” the state of wakefulness. It is coordinated with the rest of the body to kickstart the process that allows you to fall asleep in the evening. This includes blocking activity from wake‐promoting regions of the brain.
Adenosine and Sleep
Adenosine is the by‐product of neuron activity during the day which is something we mentioned at the beginning of the section. Adenosine levels fluctuate depending on how long you’ve been awake. This is why humans tend to feel sleepier the longer they stay awake. The build‐up of adenosine starts to inhibit regions of the brain associated with wakefulness, thus impacting alertness, attention, and memory.
Adenosine directly impacts the regions of the brain associated with wakefulness, such as the hypothalamus (where orexin lives) and the brain stem (acetylcholine lives). Adenosine has a big role to play in making sure your brain rests after a hard day of work.
Melatonin and Sleep
Melatonin is the chemical most people point to when it comes to brain chemistry and sleep. It’s probably the most well‐known.
Melatonin is released by the pineal gland and is incredibly sensitive to light. It is responsible for maintaining your body clock/circadian rhythms, ensuring you sleep and wake at sensible times.
Problems with melatonin production can arise in people who work night shifts or who are experiencing jet lag. Your brain starts to produce melatonin at inconvenient times, thus resulting in drowsiness and sleepiness when you would rather be awake.
The interaction between neurotransmitters, brain chemicals, hormones, and sleep patterns is a complex area in neurology and psychology. There is too much to go over in just one article and there is more information coming out every year on the subject.
Much of what we know about neurochemicals is still in its infancy. Chemicals tend to interact and it’s not always clear how they behave or influence behaviour. Nonetheless, this article has provided a simplified overview of the subject, as well as insight into the internal processes of your sleep and waking cycles.
If you want to know how Sleep and Snooze can provide a superior sleeping environment to ensure you get the best sleep possible, see our selection of products or get in touch with the team today.
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