A woman enjoying a rest among some daisies

Sleep Cycles Explained

In the past, scientists thought that as people moved from a state of consciousness to sleep, their bodies and brains went into their own form of standby. It was thought that being in shutdown meant people entered a state of passiveness that gave them the chance to recuperate from the stresses and strains of the day.

Thanks to around 70 years of research and progression in this field, experts have come to understand that sleep is actually significantly more complex. One of the standout things is the fact that sleep is a far more active state than you’d think. The truth is that when you’re in the Land of Nod, your brain is working through a number of sleep stages that vary your brain’s activity.

There are two clear parts; Non-REM (“Rapid Eye Movement”) sleep and REM sleep. Within Non-REM sleep, there are four sub-stages which we will explain in more detail.

Now that you know what happens when you’re fast asleep, here are the finer details on what happens to your brain and body as you pass through each phase of sleep.

Stage One

When you lay your head down and close your eyes, within minutes of drifting off, your brain releases alpha and theta waves. Alpha waves assist with overall mental coordination, calmness and mind/body integration, among other things. Theta waves are known for being a source of memories, emotions and sensations, as well as some other brain activity.

Additionally, stage one of your sleep cycle sees your eye movements slow down. The introduction to sleep as you move into it is fairly short-lived and typically only lasts up to seven minutes. This is a light sleep stage, therefore, you’re still going to be somewhat alert and you can also be woken up with ease.

  • Stage one fact: This is the stage where catnaps occur.

Stage Two

Moving into stage two of your sleep cycle – another reasonably light stage – this is when your brain begins to produce sharp upsurges in brain wave frequency, referred to as sleep spindles. You need sleep spindles because they play a vital role not just in sensory processing but also long-term memory consolidation.

Your brainwaves then start to slow down. This is the stage that you’d be in if you were enjoying a power nap. It’s worth noting that naps and sleep have developed a bad reputation over the years, and can be seen as a lazy trait. However, sleep and power naps, in particular, are good for improving your alertness and motor learning skills. What’s more, studies have shown that longer naps help enhance memory and boost creativity.

A couple in bed having benefitted from a sound night’s sleep

Stages Three & Four

This stage is where you move into the start of deep sleep. During stages three and four, the brain starts the process of producing slower delta waves. The deeper and slower these waves are, the more relaxed you become. You’re also still in a stage whereby no eye movement or muscle activity exists.

It’ll now be harder for you to be woken up, which is a result of your body becoming less responsive to external stimuli. As you move deeper into these stages, your brain will create even more delta waves and you will advance into an even more restorative and deeper state of sleep. At this point, it is the hardest time to be woken up from your slumber.

While you rest, your body is busy repairing muscles and tissues, as well as stimulating development and growth. What’s more, immune function is enhanced and energy is built up ready for you to tap into the following day.

Rapid Eye Movement (REM) Sleep

After working your way through the previous stages of sleep, you arrive at the final stage – REM sleep. This typically takes around an hour and a half from initially drifting off with each REM stage able to last for up to 60 minutes. For the average adult, six REM cycles per night are the norm.

While you’re in this final stage of the sleep cycle, your brain is at its most active which is why the majority of dreaming takes place here. Your eyes begin to twitch swiftly in various directions, your heart rate and blood pressure rise and your breathing speeds up, becoming shallow and irregular (there’s nothing to be concerned about here, this is perfectly normal).

REM sleep is essential for memory function and learning development because this is when your brain works to process and establish information from your day so that it can then be saved in your long-term memory.

On an average night, you will continually move through sleep cycle stages. The majority of non-REM sleep happens early in the night and the length of REM periods expand as your night goes on. This is the reason why there’s every chance you’ll wake up from a dream in the morning.

Black and white image of a female sleeping peacefully

Are you having difficulty reaching sound slumber? Hemp oil to help sleep can be used as an effective aid to support healthy rest. Our hemp oils support your body’s natural sleep patterns, helping you to feel rejuvenated the next day. Want to learn more? Check out our blog where we answer the question how does hemp work?