You may not realise it while you’re snoring away, but not all sleep is the same. During the night your body moves through five distinct sleep stage in a looping cycle. Each stage is marked by different physiological and neurological changes.

Use the diagram and the descriptions below to understand your sleep stages. By understanding how you sleep and what normal sleep patterns look like, you’ll be able to help yourself and your family sleep sounder every night.

It’s important to remember that different phases occur at different durations at different ages.

The 5 Sleep Stages

Stage 1 (light sleep)

• Body: Breath and heartbeat regulate, muscles relax, temperature drops. Some people twitch.
• Mind: Starts to withdraw from reality. Become less aware of external stimuli.
• Timing of stage: 13-17 minutes.
• Duration of stage: 10% of the night, only occurs once (not repeated like subsequent stages unless you wake up).
• Waking: The slightest noise will be enough to wake you, and you might not even realise you were asleep at all. Some people get jolted awake with a sensation of falling, it's often in this stage that people experience ‘catnaps’

Stage 2 (light sleep)

• Body: Muscles relax even more. Eyes remain still.
• Mind: Deeper sleep with less awareness of external sensations. Brain activity occurs at a lower frequency.
• Timing of stage: 15-20 minutes.
• Duration of stage: Recurring throughout the night, making up approximately half of total sleeping time.

Stage 3 (deep sleep)

• Body: Completely relaxed. Muscular activity decreases even further and our eyes remain still.
• Mind: Disconnected from reality.
• Timing of stage: 15-25 minutes.
• Duration of stage: Stages 3-4 make up around 20% of our sleep
• Waking: Make a lot of noise or shake them hard.

Stage 4 (deep sleep)

• Body: Completely relaxed. Muscular activity decreases even further and our eyes remain still.
• Mind: Disconnected from reality. Most restful sleep stage.
• Timing of stage: 35-55 minutes.
• Duration of stage: Stages 3-4 make up around 20% of our sleep
• Waking: Almost impossible—it’s a bit like trying to wake a hibernating bear!

REM stage (dream sleep)

• Body: Changes sleeping position. Heart rate increases, breathing gets quicker. Muscles remain relaxed but eyes make quick movements (Rapid Eye Movement, hence REM sleep). Increased blood flow to genitals. The stomach produces more digestive juices.
• Mind: Activity in the brain creates small, rapid movements on an EEG, similar to those seen when falling asleep. The brain is almost as active as it is when we’re awake.
• Timing of stage: 90 minutes.
• Duration of stage: 20% of the total night’s sleep for adults, more for infants and small children.

The sleep cycle

One complete cycle of these sleep stages takes around 90-110 minutes, so we repeat the cycle (except for stage 1) several times throughout the night. As the night progresses we spend less time in stages 3-4 and more time in REM stage – up to 30 minutes during our last cycle.

Our sleep cycles change as we grow. Babies spent the majority of their sleep time in the REM stage, and people over 80 years of age spend only around 15% of their time in REM sleep.

Each sleep phase works to regenerate our body’s systems and enable our brain to process what it’s learned throughout the day. That’s why getting a good night’s sleep is incredibly important for body, mind, and spirit.