How Much Deep, Light, and REM Sleep Do You Need?

Depending on age, people require between 7 and 17 hours of sleep within a 24-hour period. However, mere sleep quantity isn’t sufficient — restorative deep sleep is vital for health and functioning. Most adults typically need roughly 1.5–2 hours of deep sleep each night.

The Centers for Disease Control and Prevention (CDC) recommend that adults aged 18–60 aim for 7–9 hours of sleep per night. Approximately 1.5–2 hours of that should be deep sleep.

Sleep unfolds in stages, and we spend varying amounts of time in light and deep sleep. Every phase has value, though each performs different roles.

Below, we describe the sleep stages, clarify what deep sleep entails, and explain how much you should get.

The stages of sleep

Here are some key points about sleep stages:

• Each sleep cycle includes two broad types:
  • rapid eye movement (REM) sleep, and
  • non-rapid eye movement (NREM) sleep, which itself has three stages
• NREM breaks down into three phases:
  • N1 — light sleep
  • N2 — deeper sleep
  • N3 — the deepest NREM sleep
• A person moves through these stages roughly 4–5 times each night.
• The sequence typically runs: N1 → N2 → N3 → N2 → REM.
• Each cycle lasts about 90–110 minutes.
• The initial REM episode is brief, and REM periods lengthen as the night progresses relative to NREM.

The table below summarizes the stages of sleep.

Stage    REM or NREM    % of sleep    Approx. minutes    Characteristics

Wake/alert — — — — The person is awake and relaxed. This range covers the time from eyes-open alertness to when drowsiness begins and eyes close.

N1 (NREM stage 1): Lighter sleep — NREM — ~5% — 1–5 minutes. The person is asleep but muscle tone and breathing are similar to wakefulness.

N2 (NREM stage 2): Deeper sleep — NREM — ~45% — ~25 minutes in first cycle. This stage lengthens across cycles. Teeth grinding (bruxism) can occur here.

N3 (NREM stage 3): Deepest non-REM sleep — NREM — ~25% — ~105 minutes total across cycles. This deepest stage supports tissue repair and regrowth, bone and muscle building, and immune strengthening. Night terrors, sleepwalking, and bedwetting can happen. People are hard to rouse and may feel groggy for 30–60 minutes if awakened.

REM sleep — REM — ~25% — ~10 minutes in the first cycle, increasing later. REM is associated with dreaming and is not as physically restorative. Eyes and respiratory muscles are active, while skeletal muscles are effectively paralyzed. Breathing can be irregular. REM generally begins about 90 minutes after falling asleep and follows the other stages.

How much deep sleep is ideal?

In healthy adults, roughly 20–25% of sleep is deep NREM sleep. If you sleep 7–8 hours, that equates to about 105–120 minutes (around 1 hour 45 minutes to 2 hours) spent in the deepest sleep.

As people age, they generally require less of this very deep sleep and spend a larger proportion of the night in N2.

During deep sleep, multiple vital processes occur, including:

• muscle relaxation
• increased blood flow to muscles
• slower heart rate and breathing
• tissue growth and repair
• release of essential hormones

Without sufficient deep sleep, these restorative actions are impaired and symptoms of sleep deprivation can appear.

How much REM sleep do you need?

There’s no firm consensus on an exact REM quota, but REM is important for dreaming and emotional processing.

For most adults, REM occupies about 20–25% of total sleep, which is generally considered healthy for normal sleep cycles.

How much light sleep do you need?

There is no set minimum for light sleep. It’s nearly unavoidable if you’re sleeping, as light sleep is a natural and necessary part of the cycle.

How much deep and light sleep do children need?

Children and infants require more sleep than adults. Newborns need the most — around 14–17 hours within 24 hours.

Infant sleep includes:

• quiet sleep, resembling NREM
• active sleep, similar to REM
• indeterminate sleep

They typically experience only one or two cycles per sleep episode.

As children age, their total sleep requirement declines.

Here are the typical sleep guidelines for children:

Age    Sleep per 24 hours

0–3 months: 14–17 hours, with the longest stretch lasting several hours

4–12 months: 12–16 hours, including naps

1–2 years: 11–14 hours, including naps

3–5 years: 10–13 hours, including naps

6–12 years: 9–12 hours

13–18 years: 8–10 hours

Signs that a child may have sleep problems include:

• irritability
• difficulties with learning and memory
• frequent illness

However, the precise proportions of deep, light, and REM sleep that children and teens require at each developmental stage are not definitively established.

How can I get more deep sleep?

People may miss out on deep sleep if they:

• don’t spend enough time sleeping
• toss and turn frequently during the night
• work irregular shifts or sleep during daytime hours
• have jet lag from crossing time zones often
• have medical conditions that disrupt sleep

You can’t directly force your brain into deep sleep, but certain habits can boost your chances of getting sufficient high-quality sleep.

Helpful measures include:

• practicing stress-management techniques
• setting consistent sleep routines, such as a warm bath before bed
• sleeping in a quiet, dark room at a comfortable temperature
• using an eye mask to block light
• exercising during the day but avoiding vigorous activity in the hours before bedtime
• avoiding heavy meals, caffeine, nicotine, and alcohol near bedtime
• trying relaxation exercises or meditation
• getting up to do a calming activity like reading if you can’t sleep
• keeping phones and other devices out of the bedroom

Various sleep trackers can help you monitor patterns and estimate how much light, REM, and deep sleep you’re getting.

For additional sleep-related products, see our sleep shop.

Why do I get so little deep sleep?

If you’re 18–60 years old and sleeping 7–8 hours nightly yet still not waking refreshed, you may not be achieving enough deep sleep.

Consider consulting a doctor about a sleep study to map your sleep architecture; diagnosis and treatment of a sleep disorder might be necessary.

Potential causes of disturbed sleep include:

• obstructive sleep apnea
• pain or other symptoms that interfere with rest
• REM sleep behavior disorder
• narcolepsy
• mental health conditions such as depression or anxiety
• advanced age
• dementia
• traumatic brain injury
• certain medications

Feeling tired may reflect either insufficient sleep or excessive sleep that lacks proper restorative stages.

Impact of sleep deprivation on the body

Good-quality sleep is as essential to health as nourishment and hydration.

Quality sleep supports systems such as:

• the immune system and disease resistance
• healthy metabolism
• brain, cardiac, and lung function
• emotional regulation and mood

Poor sleep quality is associated with increased risk of:

• obesity
• high blood pressure
• type 2 diabetes
• cardiovascular disease
• depression

Frequently asked questions

Is 45 minutes of deep sleep enough?

An adult aged 18–60 should aim for 7–9 hours of sleep in 24 hours. About 1.5–2 hours (roughly 105 minutes) of that is typically deep sleep, so 45 minutes of deep sleep alone would generally be insufficient.

Keep in mind sleep cycles distribute deep sleep across the night, so the total may not occur in one continuous block.

What happens if you don’t get the right amount of deep sleep?

During deepest sleep, the body undertakes repair and rebuilding of tissues, bone and muscle formation, and immune reinforcement.

Lack of adequate deep sleep can increase vulnerability to physical and mental health problems and cause daytime sleepiness.

How do I increase my amount of deep sleep?

There’s no guaranteed way to force deeper sleep, but you can improve your odds by following these practical steps:

• keep consistent sleep–wake times, rising and retiring at the same hours daily
• make your bedroom as quiet, comfortable, and restful as possible
• remove electronic devices from the sleep environment
• adopt a calming bedtime routine, such as a warm shower or soothing music

Which is better, REM or deep sleep?

All sleep stages are important; none is inherently superior. A healthy balance typically includes about 20–25% REM and around 20–25% deepest NREM sleep to support overall wellbeing.

Takeaway

Achieving the right balance of sleep stages is crucial for health. Sleep cycles include light NREM, deep NREM, and REM sleep.

REM is when dreaming commonly occurs, while the deepest NREM phase is when the body fully relaxes and repairs itself.

Sleep needs vary by age, but the CDC advises adults to aim for 7–9 hours in 24 hours, and getting about 1.5–2 hours of deep sleep is important for feeling refreshed and preserving health.

If you struggle with sleep or daytime alertness, consult a healthcare professional, since good-quality sleep is fundamental to health and wellbeing.