Understanding Sleep: Rem Vs Non-Rem Explained

Sleep is a complex and mysterious process that humans spend about a third of their lives doing. During sleep, the body cycles through two distinct phases: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. These phases differ in several key ways, including brain activity, eye movements, and the types of activities the brain engages in. Understanding these differences is crucial for comprehending the role of sleep in maintaining overall health and cognitive performance.

Non-REM sleep is restorative, accounting for 75%-80% of total sleep time

Non-REM sleep is divided into three stages. The first is the transition between wakefulness and sleep, where the brain slows down, as does the heartbeat, eye movements, and breathing. The body relaxes, and muscles may twitch. This stage lasts around five to ten minutes. The second stage is a deeper sleep, where the body temperature drops, eye movements stop, and breathing and heart rate become more regular. This is also when the brain begins to produce bursts of rapid, rhythmic brain wave activity, which are thought to be a feature of memory consolidation. The third stage is deep sleep, where the body is fully relaxed, muscles are completely relaxed, blood pressure drops, and breathing slows. This is the stage when the body starts its physical repairs, and when declarative memories are consolidated.

The amount of time spent in non-REM sleep changes throughout our lives. For example, REM sleep is half of an infant's total sleep time but drops to about 25% by the age of ten.

Non-REM sleep is when the brain is quieter and slower

Non-REM sleep is divided into three stages, the first of which is the transition between wakefulness and sleep. In this stage, the brain slows down, and the heartbeat, eye movements, and breathing slow with it. The body relaxes, and muscles may twitch. This stage lasts for around five to ten minutes.

The second stage is a deeper sleep, where the body temperature drops, eye movements stop, and breathing and heart rate become more regular. The brain also begins to produce bursts of rapid, rhythmic brain wave activity, known as sleep spindles, which are believed to be a feature of memory consolidation.

The third stage is deep sleep or slow-wave sleep, where brainwaves, breathing, and heartbeat slow right down, and the body is fully relaxed. This is the stage where sleepwalking and bedwetting typically occur, and it is harder to wake someone during this stage.

Non-REM sleep is when the body starts its physical repairs, and the brain consolidates declarative memories. Growth hormones are released, enabling the repair and growth of bones, muscles, tissues, and organs. The brain cells also undergo repair, and the immune function is restored. Additionally, the hormones that regulate hunger and fullness are balanced during this stage, which is why weight issues can occur in people with unhealthy sleep patterns.

The amount of time spent in non-REM sleep changes throughout our lives. For example, REM sleep is half of an infant's total sleep time but drops to about 25% by the age of ten. This reflects our changing developmental needs at different ages.

Non-REM sleep is when the body repairs and restores itself

Non-REM sleep is divided into three stages, which become progressively deeper. The first stage is the transition between wakefulness and sleep, and it is easy to wake someone during this brief period. In the second stage, the body temperature continues to drop, eye movements stop, and breathing and heart rate become more regular. The third stage is deep sleep, and it is difficult to wake someone during this period.

During non-REM sleep, the body produces slow brain waves known as delta waves. This is when the body starts its physical repairs and growth. Growth hormones are released, enabling the repair and growth of bones, muscles, tissues, and organs. The immune system is also strengthened during this time.

Non-REM sleep is important for maintaining physical health and consolidating memories. It is also a time when the body can remove waste products from brain cells, which can be damaging if they are not removed. Additionally, the hormones that regulate hunger and fullness are balanced during non-REM sleep, which is important for weight management.

Overall, non-REM sleep is a crucial restorative phase that helps the body repair, restore, and reset for the coming day.

REM sleep is when the brain is active and oxygen usage increases

During REM sleep, the brain is highly active and resembles the brain activity of a waking person. Brain metabolism can increase by up to 20%, and the brain uses more oxygen than when a person is awake.

REM sleep is when most dreams occur, and it is associated with irregular breathing and a faster pulse and blood pressure. It is also when the brain processes emotions and emotional memories, and it is thought to be important for learning. The brain replays the events of the day, removing distracting background noise and saving important information in long-term memory.

The first REM cycle is the shortest, at around 10 minutes, but each cycle gets longer, with the final one lasting up to an hour. The brain is aroused with mental activities during REM sleep, but the body is temporarily paralysed, preventing sleepers from acting out their dreams.

REM sleep is when dreams occur

REM sleep typically begins around 90 minutes after falling asleep, and the first cycle is the shortest, lasting about 10 minutes. Each cycle gets longer, with the final one lasting up to an hour. The last phase of REM sleep is in the morning and is thought to be the longest, meaning most dreaming occurs early in the morning.

During REM sleep, the brain processes the day's thoughts and new information, assimilating it with existing knowledge. It is a time when the brain comes up with new ideas, and it is thought that the concept of "sleeping on it" is valid when trying to solve a problem. The brain replays the events of the day, removing distracting background noise and saving important information in long-term memory. It also reviews long-term memories, rearranging and removing unnecessary information.

REM sleep is also when emotions and emotional memories are processed and stored. It is an important stage for learning as the brain cements information into memory.

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