4 Sleep Stages: Understanding What Your Mind & Body Go Through At Night

sleep stages

Ever wonder what your mind goes through when you sleep?  There’s actually a lot more going on that you would think. Out of the four different sleep stages, three consist of Non-Rapid Eye Movement and one stage consists of Rapid Eye Movement, or REM sleep. Before the discovery of REM sleep in the 1950s by Dr. Nathaniel Kleitman, sleep was thought to be a passive state in which the mind completely shut down. However, it is quite the opposite. Our minds are active while we sleep, form memories, regulate our metabolism and remove toxins from the brain.  Here we break down the different sleep stages and what happens during each one:


The first stage begins the sleep cycle. This is a non-REM stage where you transition back and forth between consciousness and sleep. Typically, this stage is when you are at your lightest sleep and can easily awaken. This is a short period that last approximately 7-8 minutes. Brain waves, heartbeat and breathing begin to slow down allowing for a sense of deeper sleep which translates over to the next stage of the cycle.


During the second sleep stage your heartbeat and breathing patterns continue to stem into a deeper relaxation. This lasts approximately 10-25 minutes in which brain activity begins to slow down even further and body temperature decreases. Although this is still a non-REM stage, we normally spend most of our repeated sleep cycle in stage two.


The last non-REM stage is a state of deep sleep that you need to feel refreshed in the morning, according to the National Institute of Neurological Disorders. During this 20–40 minute period, breathing patterns and heartbeats slow to their lowest levels.  This is when tissue repair, growth of cell regeneration, and strengthening of the immune system occurs. While in stage three, muscles are most relaxed making it difficult to awaken.


The final stage of the sleep cycle, better known as the REM stage, occurs about 90 minutes after falling asleep. During the REM state, limb muscles become temporarily paralyzed preventing you from acting out your dreams. Most dreams occur during this stage, although some can also occur during non-REM sleep. On the contrary from the initial stages, the heartbeat and breathing patterns accelerate allowing brain activity of a person to also increase closer to that seen in wakefulness.


Knowing what your body goes through during the different stages of sleep can help us try to improve each stage individually to get better consistent sleep overall.  But how do you know how much sleep you should be getting?  Check this article out to learn more.