Everything to Know About the Stages of Sleep

Stages of sleep

Sleep can be divided into 2 phases — non-rapid eye movement (NREM) and rapid eye movement (REM) — and 4 stages that make a complete cycle. You’ll typically complete 4 to 6 cycles per night.

The first 3 stages, part of the first phase, are called non-REM sleep (N1 through N3). The final stage and second phase is REM.

NREM stage N1

Stage N1 is the transition from wakefulness to sleep.

It generally lasts only a few minutes and is the lightest stage of sleep. If you’re awoken from N1, you usually don’t perceive that you were actually asleep.

In this stage:

• eye movements are typically slow and rolling
• heartbeat and breathing slow
• muscles begin to relax
• brain waves begin to slow

NREM stage N2

Stage N2 comprises the largest percentage of total sleep time. It’s a lighter stage of sleep from which you can still be awoken easily. This is the stage before you enter deep sleep.

You may also experience:

• slower heartbeat and breathing
• no eye movements
• a drop in body temperature
• slower brain waves but still showing brief bursts of activity

NREM stage N3

The final stage of non-REM sleep, N3, is the deepest sleep stage. Your body performs various health-promoting functions in this stage.

You may also experience:

• difficulty being awoken
• even slower heartbeat and breathing
• no eye movements
• a fully relaxed body
• slower brain waves, indicating healing and restorative sleep
• tissue repair and growth
• cell regeneration
• your immune system strengthing

REM stage R

Stage R occurs about 90 minutes after you fall asleep. This stage lasts roughly 10 minutes the first time and increases with each REM cycle. Stage R’s final cycle may last roughly 30 to 60 minutes.

Stage R is typically when you dream. You may likely experience:

• rapid eye movements behind your closed eyelids
• faster and more variable breathing
• increased blood pressure and heart rate
• muscle paralysis, but twitches may occur
• brain activity similar to that of being awake

You cycle through all of these stages of sleep 4 to 6 times — roughly every 90 minutes — when you fall asleep.

What sleep disorders can disturb your sleeping patterns?

Sleep disorders can negatively impact sleep quality, which in turn can lead to other health problems.

Insomnia

Insomnia is a chronic sleep condition characterized by difficulty sleeping. Some people have trouble falling asleep, others can’t stay asleep, and some have trouble with both.

Insomnia often causes excessive daytime sleepiness and fatigue.

Cognitive behavioral therapy (CBT) is the primary treatment for insomnia. CBT may also be combined with sleep medications, which may help you fall and stay asleep. Improving sleep hygiene may also help.

Sleep apnea

Obstructive sleep apnea (OSA) is when you briefly stop breathing during sleep because the airways of your throat become too narrow to allow airflow.

The first-line treatment for OSA is a continuous positive airway pressure (CPAP) machine. A CPAP machine creates enough airflow for someone with OSA to breathe properly during sleep.

If a CPAP machine doesn’t help, bilevel positive airway pressure (BiPAP or BPAP) may help you tolerate the pressures. Sometimes, an oral appliance or surgery may be necessary.

Restless legs syndrome (RLS)

RLS is a neurological disorder that causes an uncomfortable feeling in your legs. This feeling occurs in the evening as bedtime approaches and when you’re resting or trying to fall asleep.

Because of these symptoms, people with RLS often have trouble getting enough sleep.

Certain medications are FDA approved to help manage symptoms. Proper sleep hygiene may also help relax your body before bed and make it easier to fall asleep.

Narcolepsy

Narcolepsy is a chronic central nervous system disorder that causes extreme daytime sleepiness with “sleep attacks” and low quality sleep at night. People with type 1 or type 2 narcolepsy often experience extreme disruptions in their daily life.

Medications for narcolepsy, like stimulants and SSRIs, treat symptoms of narcolepsy. Home treatments, like proper sleep hygiene, diet, and regular exercise, may help promote healthy sleep.

Managing narcolepsy can be challenging. Making adjustments in your daily schedule may help, which includes strategic napping. Support groups and counseling can help you and your loved ones cope with narcolepsy.

How can you improve your sleep?

Getting 7 to 9 hours of sleep nightly, which is how much most adults need, can be difficult. Here are some sleep hygiene tips to help improve your sleep quality and duration.

• Spend time in the sun: Exposing your body to natural light in the daytime may help maintain a healthy circadian rhythm.
• Exercise or move your body: At least 30 minutes of exercise is a great way to possibly increase your sleep duration.
• Limit your naps: Napping has benefits, but napping for longer than 30 minutes can leave you wide awake when it’s finally time for bed. Try to limit your naps to no more than 20 to 30 minutes.
• Avoid stimulants and certain foods: Nicotine or alcohol before bed may interrupt your sleep, as can foods that cause indigestion or caffeine.
• Limit your screen time an hour before bed: TVs, phones, and other electronic devices emit blue light, which may decrease your sleep quality and duration.
• Create a comfortable bedroom environment: A comfortable mattress, pillow, blanket, and other relaxing bedroom items, may help you sleep better.

Incorporating these tips slowly over time can greatly improve your sleep quality. But if you’re still having trouble falling or staying asleep, it may be time to speak with a doctor to discuss other options.

Takeaway

Your body cycles through the 4 stages of sleep — 3 stages of non-REM sleep and 1 stage of REM sleep — about 4 to 6 times each night. These sleep cycles affect your breathing, heart rate, muscles, and brain waves differently.

Getting enough sleep is necessary for important body functions like digestion, growth, and memory. Certain sleep disorders, like insomnia, may affect your sleep quality and cause difficulty functioning throughout the day.

Proper sleep hygiene can help you manage these conditions and get the sleep you need. Make sure to speak with your doctor to address any underlying health conditions and discuss which treatments might be right for you.