The 4 Stages of Sleep

As you sleep, your brain cycles through four different sleep stages, each linked to specific brainwaves and neuronal activity.

Stages 1 to 3 are non-rapid eye movement sleep (NREM), while stage 4 is rapid eye movement sleep (REM). You can think of these as light and deep sleep stages, with each stage repeating itself several times.

This article explores the basics of the four sleep stages, revealing what happens to your brain and body while you sleep.

Let’s jump in!

Sleep stages

There are four sleep stages:

• NREM stage 1
• NREM stage 2
• NREM stage 3
• REM sleep (stage 4)

These follow the logical order of light to deep sleep, although your brain cycles through them rather than sticking to any stage. You can think of the stakes are wake, light sleep, deep sleep, and REM sleep. Deep sleep and REM sleep are the most important to human health.

The 4 Stages of Sleep - NREM stage 1

Stage 1 sleep is the transition between wakefulness and sleep. Your brain, heart rate, and breathing slow down, and your muscles relax.

NREM stage 1 lasts five to ten minutes. The brain remains active, emitting high amplitude theta waves and slow brainwaves in the frontal lobe. You can think of it as a cooling-down stage that prepares your body for sleep.  

The 4 Stages of Sleep - NREM stage 2

Stage 2 sleep accounts for around 50% of total rest, with the brain producing rapid bursts of rhythmic brainwaves linked to memory.

During this stage, you become less aware of your surroundings, your eye movements stop, and your breathing and heart rate become regular.

Your body starts slowing down during stage 2 in preparation for deeper sleep, where the brain and body repair themselves. During stage 2, you can be startled but not woken as quickly, with it lasting fifteen to twenty-five minutes.

The 4 Stages of Sleep - NREM stage 3

Stage 3 sleep is linked to slow brain waves known as delta waves, which consolidate memories and information. During stage 3, your muscles switch, your blood pressure drops, and you drift off, unaware of your surroundings.

This sleep stage is brief but crucial to preparing your body for REM sleep. It disappears after around forty minutes and is only activated briefly at night.

The 4 Stages of Sleep - REM sleep (stage 4)

REM sleep closely activates your brain activity to resemble waking hours, but your body is paralysed, letting your brain work powerfully. Your body relaxes, your breathing gets faster and irregular, your eyes move rapidly, and you have dreams.

Studies have linked REM sleep to emotional memory processing, and it’s also necessary for cell repair and rebuilding. Hormone secretion occurs during stage 4 sleep, and your immune system enters overdrive.

Without adequate REM sleep, you will have mental and physical fatigue. A total lack of sleep leads to significant physical and psychological deterioration.

Sleep stage sequence

With a typical night’s sleep, the sleep stage sequence is as follows:

• Steep stage 1
• NREM sleep stage 2
• NREM sleep stage 3
• NREM sleep stage 2 repeat
• REM sleep

Your brain cycles through sleep stages in the night, activating them as it sees fit to form neural pathways and activate metabolic processes. Sleep stages are repeated four to six times, hence the importance of getting enough sleep.

What happens If I don’t get enough sleep?

A lack of sleep reduces the frequency and quality of all sleep stages, limiting the formation of neural pathways in the brain. The brain cannot cleanse itself of toxins, and the body can’t release hormones that regulate bodily processes.

One night of poor sleep makes you irritable, dizzy, and low on energy; several nights of poor sleep will significantly impact your mental and physical performance. Chronic lack of sleep puts you at risk of multiple health problems.

Top 3 mattress brands for a sound night’s sleep

1. Sleepeezee
   
   Sleepeezee was established in 1924 by the Price family, a British manufacturer based in Kent. The company holds a Royal Warrant from The Princess of Wales.
   
   So you can be sure that their products are of the highest quality. They represent the best in British design and craftsmanship, being the first manufacturer to produce pocket spring interior mattresses.
   
   Sleepeezee is the first UK mattress manufacturer to receive the Planet Mark accreditation and has drastically reduced carbon emissions and energy and water consumption, leading to recognition by the Furniture Industry Sustainability Programme. With the last waste going to landfill in 2012, the brand will be fully carbon-neutral in 2017.
   
   All products that use timber are Forestry Stewardship Council certified. They are an advocate for the Campaign for Real Wool, with the mattresses containing natural and breathable British wool. Every detail is thoroughly checked for quality and consistency, reassuring their customers that the product they are receiving will give them a good night’s sleep.
   
   They donate to the British Heart Foundation and Battersea Dogs and Cats Homes and fundraise with Macmillan Cancer Support and Crisis.
   
2. Silentnight
   
   The company was founded in 1946 by Tom Clarke and is the largest UK manufacturer of beds and mattresses in Lancashire. The company HIG Europe acquired the company in 2011.
   
   They are the only sleep brand committed to achieving Net Zero Carbon by 2040, making all their products eco-friendly, reducing fuel consumption, and cutting out C02 by 1 million kilos in 5 years with Transport and Delivery Management Technology.

3. Deepsleep

A family-run business located in West Yorkshire that has been manufacturing divan beds and mattresses for over 30 years, they have grown into one of the UK’s largest bed manufacturers.

They cater to everyone, and their three central values are comfort, quality, and value. They have an extensive range of products, including open coil, sprung, and memory foam mattresses. They also have an exclusive back care range.

Related pages

• Insomnia – 10 Practical ways to beat it
• How To Fix Your Sleep Schedule and Get a Good Night’s Rest in 2022