Measuring Rem Sleep: Advancements In Understanding Sleep Better

REM sleep, or rapid eye movement sleep, is a vital stage of the sleep cycle. It is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. During REM sleep, your brain processes emotions, consolidates memories, and dreams. While the purpose of REM sleep is not fully understood, it is known to play a significant role in a person's health and well-being. The only way to accurately measure REM sleep is by tracking brain waves through an electroencephalogram (EEG). Wearable sleep trackers can also provide estimates of REM sleep duration and quality, but their accuracy is limited.

REM sleep is measured by tracking brain waves with an electroencephalogram (EEG)

Sleep is measured primarily by polysomnography (PSG), which is considered the gold standard for diagnosing sleep disorders. PSG reveals that sleep architecture has several distinct stages that vacillate between the non-rapid eye movement (NREM) and rapid eye movement (REM) stages.

The polysomnogram is performed by attaching non-invasive sensors to the patient to record brain activity via an EEG, eye movement, submental muscle tone, leg movements, and cardiac activity with an electrocardiogram. Oral and nasal airflow sensors, finger oximeters, and thoracic and abdominal strain gauges are also used to monitor respiratory activity during sleep.

PSG is used to identify the three stages of NREM sleep (N1-N3) and the REM sleep stage by measuring specific EEG waveform rhythms and events. These include:

• Alert wakefulness: low-amplitude mixed-frequency EEG
• Drowsy wakefulness: alpha waves with 8-13 Hz peaks
• N1 stage: 4-7 Hz Theta waves (sawtooth)
• N2 stage: 11-16 Hz spindles (bursts of waves) and 0.5-2 Hz K-complexes (biphasic waves)
• N3 stage: 0.5-3 Hz Delta waves (large and slow)
• REM sleep (stage R): theta waves or wave-like patterns

REM sleep is considered a deeper form of sleep and typically occurs later in the sleep cycle. It is usually measured with a polysomnogram, but can also be measured with "wearables" or devices worn on the body to detect sleep patterns, hygiene, and health.

REM sleep can also be measured with wearables like Fitbit, Garmin, and Apple Watch

Sleep is an essential part of our lives, and getting a good night's rest is crucial for our health and well-being. Rapid Eye Movement (REM) sleep is a phase of sleep where we dream most vividly, and it is vital for good health, memory strengthening, and stimulating brain regions associated with learning. While the importance of REM sleep is clear, how can we measure it accurately?

Traditionally, measuring REM sleep required an electroencephalogram (EEG), which involves wearing a headband that detects brainwaves and provides insights into sleep architecture. However, advancements in technology have led to the development of wearable devices that can also track REM sleep. These wearables, such as Fitbit, Garmin, and Apple Watch, offer convenient ways to monitor our sleep patterns.

Fitbit devices, such as the Fitbit Alta HR, Fitbit Charge 3, Fitbit Versa, Fitbit Ionic, and Charge 4, utilise nighttime heart rate and movement patterns to estimate the time spent in light, deep, and REM sleep. By understanding these sleep stages, users can identify and address any sleep-related issues. Fitbit's sleep tracking provides a simplified view of sleep stages, grouping them into light, deep, and REM categories. This allows users to easily access their sleep data and gain insights into their sleep quality.

Apple Watch, on the other hand, offers a Sleep app that can create sleep schedules and help users meet their sleep goals. By wearing the watch to bed, it can estimate the time spent in different sleep stages, including REM, Core, and Deep sleep. The Apple Watch also provides a Sleep Focus feature, which limits distractions before bedtime and protects sleep once the user is in bed. Additionally, it offers breathing rate tracking during sleep, providing insights into overall health.

Garmin also offers advanced sleep monitoring features on its devices, allowing users to track their sleep patterns and gain insights into their sleep quality. While specific details about Garmin's REM sleep measurement are not readily available, their products likely use similar metrics as Fitbit and Apple Watch, including heart rate and movement data, to estimate REM sleep.

With the help of these wearables, users can conveniently track their sleep patterns, including REM sleep, and make informed decisions to improve their sleep hygiene and overall well-being.

Polysomnography tests are the most accurate way to measure REM sleep

During polysomnography, electrodes are placed on your chin, scalp, and eyelids, and monitors are attached to your chest to record your heart rate and breathing. These electrodes and monitors record signals while you are awake (with eyes closed) and during sleep, including brain waves, blood oxygen levels, heart rate, breathing, and eye and leg movements. This data helps determine the amount of time it takes to fall asleep and enter REM sleep, as well as track sleep cycles and stages.

REM sleep is important for memory, learning, and overall health and well-being. It is characterized by rapid eye movements and active brain activity, and it is when most dreaming occurs. While the specific functions of REM sleep are still being studied, it is known that adequate REM sleep is vital for good health.

The only way to accurately measure REM sleep is by assessing brain waves, which can be done through an electroencephalogram (EEG). This can be achieved with an EEG headband, which is a home sleep EEG version. These devices can be worn while sleeping to determine the various sleep stages and measure the duration of REM sleep.

REM sleep is important for memory, learning, and emotional processing

Memory Consolidation

REM sleep is important for memory consolidation, the process of preserving key memories and discarding unimportant information. During REM sleep, the brain processes new learnings and motor skills from the day, deciding which ones to store as long-term memories, which ones to maintain in the short term, and which ones to delete.

Learning

REM sleep stimulates the areas of the brain that help with learning and memory. It has been found to improve the ability to learn by replenishing our capacity to do so. Sleep, particularly Stages 2 and 3 sleep, plays a role in restoring our ability to learn new information.

Emotional Processing

REM sleep is also important for emotional processing. The amygdala, the part of the brain responsible for processing emotions, activates during REM sleep. Dreams, which tend to be more vivid during REM sleep, may also play a role in emotional processing. Emotional memories are processed during the REM stage, which can help people cope with difficult experiences.

Lack of REM sleep can cause trouble concentrating, a weakened immune system, and grogginess

REM sleep, or rapid eye movement sleep, is a distinct phase of sleep where the brain is active and dreaming occurs. While the purpose of REM sleep is still unknown, it is agreed upon that it is vital to good health. Measuring REM sleep can be done through an electroencephalogram (EEG), which involves placing a headband on the forehead to pick up signals being sent throughout the brain.

A lack of REM sleep can cause a range of issues, including trouble concentrating, a weakened immune system, and grogginess. Here's how:

Trouble Concentrating

During REM sleep, the brain is active and is thought to help with procedural memory and problem-solving. A lack of REM sleep can lead to issues with cognition and problem-solving abilities, making it difficult to concentrate and perform complex tasks.

Weakened Immune System

Sleep and the immune system are closely connected. Sleep deprivation can disrupt the normal functioning of the immune system, making it easier for individuals to get sick. Studies have shown that a lack of sleep is associated with an increased risk of infections, as well as long-term health problems such as diabetes, heart disease, and cancer.

Grogginess

REM sleep deprivation can lead to fatigue and sleepiness, causing grogginess throughout the day. It can impact an individual's energy levels and ability to function optimally during the day.

Frequently asked questions