Understanding Rem Sleep: The Ideal Percentage Range

Sleep is a vital process that allows the body and mind to rest and recover. A good night's sleep is made up of four to six sleep cycles, each lasting 90 to 110 minutes. Each cycle consists of three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage. NREM sleep constitutes about 75 to 80 per cent of total sleep time, while REM sleep makes up the remaining 20 to 25 per cent.

REM sleep is the fourth and final stage of the sleep cycle

REM sleep typically begins about 90 minutes after falling asleep and lasts for around 10 minutes during the first sleep cycle. As sleep progresses, the REM stage gets longer, and the time spent in deep NREM sleep decreases. By the final REM phase, individuals may spend up to 60 minutes in this stage. Overall, REM sleep constitutes about 20-25% of total sleep time in healthy adults.

During REM sleep, the body enters a temporary state of paralysis, likely to prevent individuals from acting out their dreams. This paralysis is caused by the neurotransmitters gamma-aminobutyric acid (GABA) and glycine, which depress the parts of the brain that control muscle movement. While the body remains still, the eyes move rapidly behind closed eyelids, scanning dream imagery.

REM sleep is important for several reasons. Firstly, it aids in memory consolidation by stabilising and organising new memories formed during the day. Secondly, it plays a role in procedural memory, helping to reinforce newly learned skills. Thirdly, it contributes to brain development, especially in infancy, where up to 50% of sleep is spent in the REM stage. Finally, REM sleep is necessary for regulating emotions and emotional information processing, which is essential for mental health and emotional well-being.

REM sleep is when most dreaming occurs

REM stands for rapid eye movement. During this stage of sleep, the eyes move rapidly in different directions, and the brain is active. Brain activity during REM sleep is similar to its activity when a person is awake. Dreams typically happen during REM sleep, and they tend to be more vivid than those that occur during non-REM sleep.

During non-REM sleep, the brain is less active. In the deeper stages of non-REM sleep, breathing slows down and blood pressure drops. After falling asleep, people usually enter non-REM sleep first, followed by a shorter period of REM sleep, and then the cycle starts over again.

Each sleep cycle includes three stages of non-REM sleep and a stage of REM sleep. The first cycle of REM sleep usually occurs about 60 to 90 minutes after falling asleep. The first period of REM sleep typically lasts about 10 minutes, with each subsequent REM stage getting longer, with the final one lasting up to an hour.

REM sleep is important for several reasons. Firstly, it stimulates the areas of the brain that help with learning and memory. Secondly, it plays a role in memory consolidation, emotional processing, and brain development. Finally, it helps with wakefulness preparation, as the activation of the central nervous system during REM sleep may help individuals prepare to wake up.

While REM sleep is crucial, it is important to get sufficient non-REM sleep as well. Non-REM sleep is when the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system.

During REM sleep, the body enters a temporary state of paralysis

The neurotransmitters gamma-aminobutyric acid (GABA) and glycine depress the parts of the brain that impact muscle movement. This loss of muscle movement is likely a safety mechanism that keeps people still while they sleep.

REM sleep is also when most dreaming occurs. The eponymous eye movement is how we watch what unfolds in our dreams. Sleep scientists have confirmed that each dart of the eyes correlates with a new dream image, as if the brain is clicking through a slideshow.

REM sleep is important for memory consolidation

REM sleep is characterised by low-amplitude (small), high-frequency (fast) waves and alpha rhythm, as well as the eye movements for which it is named. During REM sleep, muscles in the arms and legs are temporarily paralysed, which is thought to be a neurological barrier that prevents people from acting out their dreams.

REM sleep makes up about 20-25% of total sleep in healthy adults. It usually occurs in the second half of the night and its duration increases as the night progresses.

Memory consolidation during REM sleep may occur through the replay of neuronal activity from prior learning episodes. However, the evidence for the role of REM sleep in memory consolidation is considered weak and contradictory. For example, human studies have shown that pharmacologically and brain lesion-induced suppression of REM sleep do not lead to memory deficits. Furthermore, there is no positive relation between REM sleep time or intensity and encephalization across species.

Despite this, sleep is clearly important for optimum acquisition and performance of learned tasks.

The amount of REM sleep needed varies depending on age

Sleep is a vital natural process that allows the body and mind to rest and recover. The sleep cycle consists of distinct stages, including NREM and REM sleep, each with a specific role in maintaining your health. The amount of REM sleep needed varies depending on age.

REM sleep is the fourth and final stage of the sleep cycle. During REM sleep, brain activity increases and both heart rate and breathing become more rapid. Your eyes begin to move quickly behind closed eyelids. This stage is highly important for brain development and memory.

During infancy, REM sleep can make up to 50% of sleep. In adulthood, REM sleep tends to last longer after periods of learning. As we age, the amount of REM sleep we need decreases. Elderly adults may need far less REM sleep.

REM sleep is important for learning and memory. During REM sleep, the brain can process new information and motor skills, committing some to memory, working to maintain others, and deciding which ones are no longer needed.

The sleep cycle lasts about 90 to 110 minutes. A typical night consists of four to six sleep cycles. The first three stages are NREM sleep, and the final stage is REM sleep.

NREM sleep can be broken down into three distinct stages: N1, N2, and N3. In the progression from stage N1 to N3, brain waves become slower and more synchronized, and the eyes remain still. In stage N3, the deepest stage of NREM, EEGs reveal high-amplitude (large), low-frequency (slow) waves and spindles. This stage is referred to as "deep" or "slow-wave" sleep.

The amount of REM sleep needed depends on how much sleep you require in general to feel rested. As a rule of thumb, adults should aim for seven to nine hours of sleep per night. Within this window, you’ll log 105 to 135 minutes of REM sleep.

If you set an alarm and wake up feeling super tired, you may need to boost your sleep time so that you can gain more REM sleep. While a little fogginess upon waking is normal, waking up extra foggy could mean you’re being jolted out of NREM3 (the deep-sleep phase) and experiencing what’s called sleep inertia.

Ideally, you’ll wake up gradually from REM sleep, which researchers theorize is meant to help us transition out of deeper sleep. As your sleep sessions progress over the course of the night, you’ll spend more time in each REM phase and less time in NREM3.

If you don’t get enough REM sleep for one or two nights because of shortened sleep sessions, you may feel grogy from not having had enough sleep cycles. Over time, you could feel more forgetful, too.

Longer-term deficits in REM sleep are associated with health concerns, including an increased risk of all-cause mortality and cardiovascular and non-cancer-related deaths.

Frequently asked questions