Wednesday Wisdom
The Neuroscience of Sleep
I love good, deep sleep and really feel the benefits of a good night as well as suffering the effect of a bad night!
Sleep is a huge subject within neuroscience as it affects our functioning, our emotional world as well as how we relate to the environment around us.
The neuroscience of sleep delves into the intricate workings of the human brain during slumber.
Do you know about sleep?
Sleep Stages:
Scientists generally recognise four stages of sleep, which we cycle through several times each night:
Non-Rapid Eye Movement (NREM) Sleep:
Stage 1: During this initial phase, the body and brain transition from wakefulness to sleep. Brainwaves shift from an active pattern to a slower rhythm, and muscle tone relaxes.
Stage 2: Body temperature drops, heart rate and breathing slow down, and brainwaves further decrease in frequency.
Stage 3 (Deep Sleep): Heart rate, breathing, and brain activity reach their lowest points. This stage is crucial for feeling refreshed upon waking.
Rapid Eye Movement (REM) Sleep:
REM sleep, where dreams occur, is the fourth stage. It typically occurs about 90 minutes after falling asleep. During REM:
Breathing becomes more rapid and irregular.
Heart rate and blood pressure increase to near waking levels.
Eyes move rapidly behind closed eyelids.
Interestingly, REM sleep decreases as we age.
Circadian Rhythms and Sleep-Controlling Neurons:
Circadian rhythms follow a daily cycle, responding to light-darkness patterns. These rhythms are genetically determined and coordinated by biological clocks within cells throughout the body.
The suprachiasmatic nucleus, a group of neurons in the brain, orchestrates these biological clocks.
Additionally, the sleep-wake homeostasis tracks our need for sleep and influences when we feel sleepy. As we stay awake, the homeostatic sleep drive increases.
Brain Activity During Sleep:
REM sleep is characterized by rapid eye movement and muscle atonia. It’s closer to wakefulness.
NREM sleep, especially the deep part known as slow wave sleep, lacks prominent eye movement and involves muscle paralysis.
Brain waves slow down during sleep, and neurotransmitters like acetylcholine become less available.
Sleep plays a housekeeping role, removing toxins that accumulate in the brain during wakefulness.
Sleep plays a crucial role in the detoxification of both the body and the brain.
Brain Detoxification:
The brain has a “waste management system” known as the glymphatic system. This system is a series of tubes that carry fresh fluid into the brain, mix the fresh fluid with the waste-filled fluid that surrounds the brain cells, and then flush the mix out of the brain and into the blood.
This process primarily occurs during deep sleep. During this phase, cerebrospinal fluid, a watery liquid that surrounds the brain and spinal cord, washes away accumulated toxins.
The toxins that are cleared out include waste proteins that accumulate during waking hours, including beta-amyloid, which is implicated in Alzheimer’s disease.
There is some evidence that chronic sleep deprivation, which reduces the function of the waste management system, may increase the risk for various brain diseases.
Body Detoxification:
During sleep, your body also works to detoxify and repair itself. The liver, which plays a central role in detoxification, is particularly active during sleep.
The liver filters the blood to remove harmful substances like toxins and waste products. It also converts toxins into water-soluble substances that can be eliminated from the body.
Furthermore, during sleep, your immune system releases proteins called cytokines. Some of these substances can promote sleep. Certain cytokines need to increase when you have an infection or inflammation, or when you’re under stress. Sleep deprivation may decrease the production of these protective cytokines. In addition, antibodies and cells that fight infection decrease during periods when you don’t get enough sleep.
So, good quality sleep is essential for the detoxification processes in both the brain and the body.
Lack of sleep, or sleep deprivation, is pretty endemic in western society and can have significant impacts on our health.
Here are some statistics that highlight the extent of the problem:
62% of adults worldwide feel that they don’t sleep well when they go to bed.
More than one-third of adults sleep less than the recommended seven hours per night, on average.
Among all states in the USA, Hawaii has the highest percentage of adults (43%) who get seven or fewer hours of sleep each night.
Worldwide, over 45% of the population gets less than the recommended seven or more hours of sleep per night.
Insomnia affects approximately 7-30% of the global population.
Obstructive sleep apnea affects at least 936 million adults worldwide.
Excessive daytime sleepiness affects 15-30% of the general global population.
In the UK Sleep deprivation is a significant issue.
Here are some key statistics:
74% of UK adults reported a decline in quality sleep over the past 12 months.
Young adults aged 35-44 got the least sleep, with almost 50% only getting 5-6 hours per night.
Only 33% get the recommended 7-8 hours of sleep per night.
1 in 10 people were getting only 2-4 hours of sleep per night.
In 2022, 34.0% of children aged 7 to 16 years had a problem with sleep 3 or more times over the previous 7 nights.
In the same year, 64.0% of young people aged 17 to 23 years had a problem with sleep 3 or more times over the previous 7 nights.
Alongside this poor sleeping comes along lots of 21st century unwellness and illnesses -
Mental Health: Sleep deprivation can negatively affect our mental abilities and emotional state. It can lead to mood swings, impulsive behavior, anxiety, depression, paranoia, and even suicidal thoughts. Chronic sleep deprivation can also trigger mania in people who have bipolar mood disorder.
Cognitive Function: Lack of sleep can disrupt how your body usually sends and processes information. This can lead to difficulties with concentration, learning new things, making decisions, and creativity. It can also increase the risk of accidents due to delayed body signals and decreased coordination.
Immune System: During sleep, your immune system produces protective, infection-fighting substances like antibodies and cytokines. Sleep deprivation prevents your immune system from building up its forces, which may result in your body being unable to fend off invaders and taking longer to recover from illness. Long-term sleep deprivation also increases your risk for chronic conditions, such as diabetes mellitus and heart disease.
Respiratory System: The relationship between sleep and the respiratory system is bidirectional. A lack of sleep can lead to a weaker immune system, making you more vulnerable to respiratory infections like the common cold and flu. Conversely, conditions like obstructive sleep apnea can disrupt sleep and lead to further sleep deprivation.
Obesity and Metabolic Syndrome: Chronic sleep deprivation is linked to an increased risk of obesity, diabetes, high blood pressure, and heart disease. This is partly due to alterations in glucose metabolism and appetite regulation associated with insufficient sleep.
So what causes poor sleep?
There are several factors that can contribute to poor sleep:
Stress, Anxiety, and Depression: These mental health issues can make it difficult to fall asleep or stay asleep.
Physical Health Conditions: Certain illnesses or conditions, such as chronic pain or frequent urination, can disrupt sleep.
Environment: A room that’s too hot, too cold, or noisy can interfere with sleep. The Environment is really important!
Lifestyle Factors: Consuming alcohol, caffeine, nicotine, or certain medications close to bedtime can disrupt sleep. Shift work or jet lag can also throw off your body’s sleep schedule.
Poor Sleep Hygiene: This includes habits like using electronic devices before bed, not having a consistent sleep schedule, and not allowing time to relax before bed.
Genetics: Some people are naturally lighter sleepers or take longer to get to sleep.
If you have not a good sleep routine it can literally make you ill, age you considerably and affect your cognitive ability and functionality. It is not something to be complacent about. A good sleep/wake cycle is essential to be well and keep well.
Understanding the neuroscience of sleep can indeed help us improve our sleep quality.
Here are some neuroscience tested suggestions that will support a good night’s sleep!
Slumber in Two Shifts: Historically, people used to have a “biphasic sleep” pattern, where they would sleep for a short period, wake up for a couple of hours, and then go back to sleep. If you find yourself waking up in the middle of the night, don’t panic. It might be your body’s natural rhythm.
Vary Your Sleep with the Seasons: Research shows that we need more sleep during the dark, cold winter months than we do during the summer. Adjusting your sleep schedule according to the season might help improve your sleep quality.
Try a Nap: Regular naps are good for our health. A short nap during the day can help refresh your mind and body.
Morning Light Exposure: Our circadian cycle, which determines when we want to be asleep or awake, is mostly governed by sunlight. Exposure to light shortly after waking up can help set off an internal timer to secrete melatonin (which helps us fall asleep) about 12 to 14 hours later.
Limit Blue Light and Caffeine: Try to limit your blue light consumption in the hours before bed as it can block the production of the hormone melatonin, which is necessary for good sleep. Also, limit or stop consuming caffeine after 2 p.m., as this chemical can throw off your sleep rhythms.
Relaxation Techniques: Practicing relaxation techniques before bed can help free your mind from the day’s encounters, conflicts, or conversations. This can help you ease into sleep.
Bedtime Routine: Establishing a bedtime routine can signal your body that it’s time to wind down and get ready for sleep. This could include reading a book, listening to calming music, or practicing relaxation exercises.
Start today and understand the importance of rest, recuperation and renewal!
Sleep is the best meditation