Sleep cycles

Healthy sleep cycles

To fully understand how narcolepsy affects the brain, first you must learn a bit about how a normal brain works…

A healthy person will get around 6-8 hours of sleep on average, and in this time they will go through several “stages” of sleep. There are two main categories for these stages: REM (Rapid Eye Movement) sleep and non-REM sleep. A normal sleep cycle will go through stages 1-4 before moving into REM, and then alternating between

Non-REM sleep makes up 75% of a normal sleep cycle and consists of stages 1-4, each typically lasting for 5-15 minutes. Stages 1 and 2 are the lighter stages of sleep, occurring just as a person begins to fall into sleep. Stages 3 and 4 are our stages of deep sleep, also known for being the “delta wave” or “restorative” sleep stages.

During these stages brainwaves slow considerably and the body has time to truly rest and repair itself: relaxing and increasing blood flow to muscles, slowing breathing and heart rate and releasing hormones essential for growth and repair.

REM sleep makes up the remaining 25% of a normal sleep cycle and typically occurs about 90 minutes after the onset of sleep. It is during this stage that most dreaming occurs; our brains are very active (sometimes more so than when we are awake), our eyes dart around rapidly, and our bodies are paralysed to prevent us from physically acting out our dreams.

Narcoleptic sleep cycles

For a person with narcolepsy, these sleep cycles are completely different.

While a person with narcolepsy may sleep the same amount of hours as anyone else, it will likely be spread out in phases throughout the day instead of being condensed into the normal 6-8 hour period.

Far from the ‘always sleepy’ stereotype, most people with narcolepsy find it extremely difficult to sleep through a whole night, sleeping for only a few hours at a time. Lost sleeping time is often made up during the day, when the narcoleptic brain will dip into sleep at inconvenient times.

As well as this altered timing, people with narcolepsy will experience their sleep stages in a different order and frequency. Stage 1 is typically increased, with stages 3 & 4 decreased. The proportion of REM to non-REM sleep is also vastly increased. People with narcolepsy can even enter REM immediately upon falling asleep.