Dangers Of Being Awake During Rem Sleep

Being woken up during REM sleep can have several negative consequences. Dubbed 'sleep inertia', the feeling of grogginess and disorientation that follows can last up to four hours, impairing your ability to perform simple tasks. This is because, during REM sleep, your brain activity is similar to how it is when you're awake, so being woken up during this stage can cause high levels of melatonin, resulting in sleepiness. In addition, being woken up during REM sleep can lead to a negative mood and self-appraisal, with women seemingly being affected more negatively than men.

REM sleep and the risk of self-harm

REM sleep behaviour disorder (RBD) is a parasomnia, or sleep disorder, that affects less than 1% of people. It causes people to act out their dreams, often violently, and can result in injury to themselves or their bed partner. This makes it a risk factor for self-harm.

During normal REM sleep, the body experiences temporary paralysis of most muscles while the brain is active and dreaming. This allows us to dream safely. For individuals with RBD, this paralysis does not occur, and they physically act out their dreams while remaining asleep.

Symptoms of RBD include vivid or frightening dreams, physical movements, and vocalisations during sleep. People with RBD may experience minor limb movements, or more pronounced body movements such as punching, flailing, kicking, sitting up in bed, or jumping out of bed. They may also talk, yell, or scream.

The risk of self-harm is increased for individuals with RBD due to the violent nature of their movements during sleep. They can put themselves and anyone they share a bed with at risk of physical injury. These injuries can be life-threatening, and up to 90% of spouses of those with RBD report having sleep issues, with over 60% experiencing physical injury.

RBD is more common in men and adults over 50, with an average age of onset of 61 years. It is strongly associated with certain neurodegenerative disorders, particularly Parkinson's disease, Lewy body dementia, and multiple system atrophy. About 97% of people with isolated RBD will develop one of these conditions within 14 years of their RBD diagnosis.

Treatment for RBD focuses on creating a safe sleeping environment and may include removing sharp objects from the bedroom, placing padding on the floor, and sleeping in a sleeping bag or on a mattress on the floor. Medications such as melatonin and clonazepam can also help reduce symptoms.

REM sleep and the brain's ability to process emotions

The amygdala, an almond-shaped structure in the brain that processes emotions, becomes increasingly active during REM sleep. This sleep stage is associated with dreaming, memory consolidation, emotional processing, and healthy brain development. Dreaming may help process emotions, as events from the day often invade thoughts during sleep, and people suffering from stress or anxiety are more likely to have frightening dreams.

REM sleep is believed to play a role in emotional processing by modulating the amygdala and other affect-related regions, including the hippocampus and anterior cingulate cortex. The unique neurobiology of REM sleep, which includes increased brain activity and elevated heart rate, may create an optimal biological environment for emotional memory processing.

Research has shown that sleep deprivation can impair the brain's ability to process emotions effectively. Sleep-deprived individuals may experience increased subjective reports of irritability and affective volatility, amplified negative emotional consequences, and a loss of functional connectivity between the amygdala and the medial prefrontal cortex. This can result in a hyper-limbic reaction by the amygdala in response to negative emotional stimuli.

Additionally, sleep plays a crucial role in regulating emotional brain function and affective brain reactivity. Sleep disorders such as REM Sleep Behavior Disorder (RBD) can cause individuals to act out their dreams, potentially leading to injuries to themselves or their bed partners.

In summary, REM sleep is essential for the brain's ability to process emotions effectively. The unique characteristics of this sleep stage, including increased brain activity and the involvement of the amygdala, contribute to the processing and consolidation of emotional memories. Sleep deprivation can disrupt these processes, leading to increased emotional reactivity and potential negative consequences.

REM sleep and the development of infants

Sleep is critical for memory, learning, and socio-emotional development in infants.

Newborns spend most of their time asleep, with sleep being the predominant state at birth. Sleep architecture changes markedly over the first two years of age, with rapid changes occurring within the first 12 weeks and continuing throughout childhood.

During the first year of life, there is an increase in non-rapid eye movement (NREM) sleep and a decrease in REM sleep. Sleep structure in early childhood is very different from that of adulthood. At birth, an ultradian rhythm dominates, and infants and young children spend a greater period of time asleep in a 24-hour period and have different electroencephalogram (EEG) patterns compared to older children and adults during sleep.

REM sleep, in particular, plays an important role in the development of infants. It is involved in brain development, with newborns spending most of their sleep time in REM. Animals born with less developed brains, such as humans and puppies, spend more time in REM sleep during infancy than those born with more developed brains, like horses and birds.

REM sleep contributes to infant learning in multiple ways. Firstly, it facilitates neural maturation, preparing infants to process and explore their environment in increasingly sophisticated ways. Secondly, it plays a role in memory consolidation of material presented while the infant is awake. Finally, there is emerging evidence that infants can process sensory stimuli and learn about their environment even while asleep.

The characteristics of infant sleep differ from those of adult sleep. Newborns sleep for at least 16-18 hours per day, and their sleep patterns are markedly different from the sleep patterns of older infants and adults. In the first year of life, there is a developmental change in sleep patterns, including an increase in quiet sleep, a decrease in active sleep, and the development of a clear circadian rhythm.

The unique characteristics of infant sleep, including a preponderance of active sleep and frequent transitions between states, may be particularly well-suited for timely learning about the extrauterine environment. Optimal sleep prepares the infant to learn when awake, and critical memory consolidation processes follow during sleep.

Overall, REM sleep plays a crucial role in the development of infants, facilitating brain maturation and learning.

REM sleep and the risk of obesity

REM sleep, or rapid-eye movement sleep, is the fourth of four stages of sleep. It is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. During this stage, the brain is highly active, and dreams occur.

The Link Between REM Sleep and Obesity

A number of studies have found a link between short sleep duration and obesity. Research suggests that this may be due to the impact of sleep deprivation on appetite regulation and metabolic function.

Sleep loss can cause metabolic and endocrine changes, such as decreased leptin levels (the hormone that suppresses appetite), increased ghrelin levels (the hormone that stimulates appetite), and insulin resistance. This can lead to increased hunger and appetite, as well as a preference for calorie-rich foods. Sleep loss also provides more time to eat over a 24-hour period and can cause fatigue and excessive daytime sleepiness, reducing daily physical activity and energy expenditure.

A study of 335 children and adolescents found that compared to normal-weight children, overweight children slept about 22 minutes less and had lower sleep efficiency, shorter REM sleep, lower REM activity and density, and longer latency to the first REM period. Another study of 5549 women found that the effect of short sleep duration was even stronger for extreme obesity.

Other Sleep Disorders and Obesity

In addition to short sleep duration, sleep disturbance and poor sleep quality may also increase the risk of obesity. For example, obstructive sleep apnea (OSA) is associated with obesity, and the sleep fragmentation, overall sleep loss, and daytime sleepiness associated with OSA may favour weight gain.

REM sleep and the risk of migraine

REM sleep is where most people spend the majority of their sleep cycle. Failing to get enough REM sleep may result in higher levels of proteins that can trigger headaches, according to researchers. This is a way that migraines may begin when you are resting. If your body isn't getting enough time in REM sleep, it can result in migraine symptoms while you are asleep, so you're hit with migraine pain when you awake.

There is a complex and poorly understood relationship between sleep and migraine. Patients with migraine have consistently reported poor sleep both before and during attacks, identifying poor sleep as a migraine trigger. However, sleep is reported to serve a therapeutic role in terminating headache.

Recent neuroscience discoveries have also more clearly delineated the role of sleep in overall long-term brain health. The recent discovery of the glymphatic system – a CNS clearing system that works primarily during sleep – provides the possibility for such a mechanism.

There is increasing neuroscientific evidence to support the idea that there may be a common underlying etiology as well. Parts of brainstem-cortical networks involved in sleep physiology are unintentionally being identified as important factors in the common migraine pathway. Recent discoveries on anatomic localization (the hypothalamus as a key and early mediator in the pathophysiology of migraine), common mediating signaling molecules (such as serotonin and dopamine), and the discovery of a new CNS waste removal system, the glymphatic system, all point to a common pathophysiology manifesting in migraine and sleep problems.

The complex relationships between sleep and migraine point to a common shared pathophysiology. Although this topic has received significantly more attention over the last 2 decades, there are still many knowledge gaps.

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