The first phase of REM usually lasts for 10 minutes, with each phase getting progressively longer. In most people, a state of temporary paralysis is experienced as the brain signals the spinal cord to cease movement of the arms and legs.
This lack of muscle activity is known as atonia, and it may be a protective mechanism to prevent injury that might be caused by acting out our dreams. REM sleep is often associated with very vivid dreams due to the increase in brain activity.
Because the muscles are immobilized yet the brain is very active, this stage of sleep is sometimes called paradoxical sleep. Each stage of NREM lasts for minutes. Stage 1 non-REM sleep — a person in this stage is between being awake and asleep or is in a state of very light sleep. Stage 2 non-REM sleep — this stage is characterized by a slightly deeper sleep. Body temperature drops and heart rate slows down. Stages 3 and 4 non-REM sleep — a state of deep and restorative sleep known as slow-wave sleep, or delta sleep.
The muscles relax, the supply of blood to the muscles increases, and the body repairs and grows tissue. Hormones are released and energy stores are replenished. As people age, they tend to get less NREM sleep.
Those under 30 usually experience 2 hours of restorative sleep nightly while older adults may get just 30 minutes. REM sleep is believed to benefit learning, memory, and mood. It is also thought to contribute to brain development in infants. REM sleep is the time when new learnings from the day are committed to memory. As a precautionary measure, your brain also sends signals to immobilize your arms and legs in order to prevent you from acting out your dreams.
REM sleep and deep sleep also referred to as slow wave sleep are very different stages of sleep. It precedes REM sleep in a normal sleep cycle, and unlike REM your heart and respiratory rate decrease during deep sleep. Your first period of REM sleep each night usually occurs within 90 minutes of falling asleep, and only lasts about 10 minutes.
The final one may last roughly an hour. If you get hours of sleep, around 90 minutes of that should be REM. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version. Overview Rapid eye movement REM sleep behavior disorder is a sleep disorder in which you physically act out vivid, often unpleasant dreams with vocal sounds and sudden, often violent arm and leg movements during REM sleep — sometimes called dream-enacting behavior.
Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. Show references Rapid eye movement sleep behavior disorder. Arlington, Va. Accessed March 24, Sateia M. It may contribute to learning and memory consolidation, although the research is not conclusive.
Specifically, it may help someone to learn a new skill. An example of this procedural memory could be learning how to ride a bicycle.
It differs from factual, or semantic memory, such as memorizing a list of vocabulary words. Beyond its role in procedural memory, it is hypothesized that REM sleep may also have a role in problem-solving.
Unique connections may be made within the brain, allowing novel discoveries to be made. The vivid dreams of REM sleep are often experienced like a movie unfolding in which the sleeping person is an actor in the story. When the content of the dream is disturbing, nightmares may result. Mood disorders like anxiety and depression and post-traumatic stress disorder PTSD may impact the experience of dreams.
If REM sleep serves a vital function, the loss of it may be worrisome. Much has been made of the impacts of sleep deprivation on health.
When insufficient sleep is obtained to meet sleep needs, there are real consequences to health and well-being.
Sleep deprivation not only causes sleepiness and the inherent risks, but it seems to wreak havoc on metabolism, pain, and cardiovascular health. How might someone become dream deprived? REM sleep normally occurs at regular intervals throughout the sleep period.
Every 90 to minutes, REM sleep may occur. These periods may last 5 to 30 minutes and typically become longer towards morning so that most REM sleep is experienced in the last one-third of the night. It is common to interrupt the last period of REM sleep upon awakening. Frequent disturbance of REM sleep may be experienced as false awakenings. There are certain situations when REM sleep may be either reduced or absent from sleep. Sleep deprivation due to inadequate total hours of sleep may lead to an absolute reduction in the time spent in REM, but the percentage of the night in REM sleep may actually increase.
This occurs because lighter sleep may be eliminated with sleep consolidation. Substance use has a profound impact on REM sleep.
Beyond these impacts, sleep disorders, especially obstructive sleep apnea and narcolepsy, may lead to fragmented periods of REM sleep. The muscle relaxation of REM may cause airway muscles to collapse and trigger breathing disturbances seen in sleep apnea.
This may curtail the persistence of REM. When sleep apnea is effectively treated with continuous positive airway pressure CPAP therapy , this may lead to a profound rebound of REM sleep. One might guess that the widespread use of alcohol and antidepressants, the high prevalence of sleep apnea, or the impacts on sleep deprivation may have profound detrimental impacts on societal health.
Unfortunately, research has not proven this out. If there is a vital process achieved by REM sleep, why is there is no discernible effect when deprivation occurs continuously for decades with chronic antidepressant use? Even subjects with permanent damage to the REM-generating part of the brain can have normal memory and no perceptible loss of function.
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