Why Does Time Go By So Fast When You Sleep?

When you wake up in the morning, does it sometimes feel as though you’ve only been asleep for a few minutes? Then you check the time and realize that 8 hours have passed in the blink of an eye. 

Why Does Time Go By So Fast When You Sleep?

In this article, we are going to take a deeper look into the deeper parts of your brain during sleep. You’ll have a better understanding of why time can go by so fast when you sleep, in addition to the stages of sleep that actually slow time down. 

Let’s start with the main question on your mind. 

Does Time Actually Pass Quicker When you’re Sleeping? 

The bad news is that you haven’t developed the ability to time travel while you were asleep. Time still passes at the same rate as when you’re awake, regardless of what you get up to. 

However, the amount of engagement your brain has in the outside and inside world is what makes the difference.

As you pass through the different stages of sleep, which we will touch on soon, your brain experiences different activity levels that can appear to slow time down and speed it up. 

Your brain is basically distracted from the normal things that you’re stimulated by, which interferes with your usual reference points for time.

The inner workings of your brain also undergo some changes during the night, which is known as the stages of sleep. 

Summary Of The Stages Of Sleep 

Your brain goes through this cycle multiple times per night, so it’s nothing to be afraid of. Most people naturally experience all the stages of sleep, therefore you’re not on your own thinking that time is speeding up or slowing down. 

Stage 1

This is your brain’s transition from being awake to shutting your eyes down. During this stage, you can be easily woken up by noises or movements around you. Even having muscle twitches is enough to jolt you awake again. 

Stage 2

Entering a deeper sleep now, your body goes through a few physical changes that prepare you for entering a full, deep sleep. Your pulse slows down, your body temperature drops and you experience fewer and fewer active thoughts. 

Stage 3 

Slow-wave sleep kicks in at stage 3 as you enter the deepest form of sleep your brain is capable of. The brain completely lets go of consciousness and starts to do all the overnight maintenance work that your body needs to recover for the next day. 

Stage 4 

The final stage is called REM sleep, standing for ‘rapid eye movement’. This is your dream state where your brain has a similar level of activity to when you’re awake.

Why Does Time Go By So Fast When You Sleep?

Slow-Wave Sleep 

At stage 3, your brain has slowed down completely due to the presence of delta waves. Slow-wave sleep is essential for helping your body recover for the following day.

From repairing your muscles and tissues to boosting your immune system, slow-wave sleep is an important part of keeping you healthy and fresh. 

Your brain blocks everything out as it prepares you for REM sleep (see also ‘What Does REM Sleep Stand For?‘). Without switching everything off before you start dreaming, your body would still be engaged enough to react during vivid dreams (see also our article on crying during sleep).

If you were dreaming about running, your legs would be moving while you were asleep. 

How Does Slow-Wave Sleep Affect Time? 

During slow-wave sleep, time can feel as though it’s passing much quicker. At least when you wake up, this can be the case.

Due to your brain being completely disengaged, you have none of your usual reference points for time that you have when you’re awake. There’s no clock or sunlight to give you an impression of how much time has passed. 

Slow-wave sleep can make it seem like you’ve blinked and hours have passed because there is nothing conscious happening in your brain. 

REM Sleep 

REM sleep has the opposite effect as slow-wave sleep as your brain switches back on and experiences a lot of activity. Time can seem like it has slowed down during this stage as your brain enters its most active phase. 

The levels of activity that you experience during REM sleep are similar to those that you have when you’re awake, which is why you’re able to have vivid dreams.

If you wake up in the middle of one of these stages, you will probably be able to remember your dreams in detail. 

How Does REM Sleep Affect Time? 

It is considered that we dream in slow motion, which is a simplified way of explaining the effects of REM sleep on time. 

Have you ever had a dream that felt like it lasted for hours, but in fact it was only a minute or two? Dreams can really deceive your brain into thinking a lot of time has passed due to the activity that it goes through. 

During the REM sleep stage, you receive an overload of stimulation. This gives your brain a barrage of reference points for the passing of time, which leaves you with the impression that hours have passed despite it only being a few minutes. 

Final Thoughts 

In summary, lower brain activity makes time pass quicker, whilst higher brain activity makes time pass slower. It can be difficult to wrap your head around, conscious or otherwise, but your perception of time changes as your brain shuts down then boots up again. 

Time still passes at the same rate as if you are awake, but it’s like watching the clock during a boring day at work. The more you focus on the hands ticking round, the slower time seems to pass.

On the other hand, if you are put under general anesthetic, you simply wake up in the recovery room without any record of what happened in the hours that have just passed. 

See if you can guess how long you’ve been asleep the next time you stir in the night. Depending on the stages of sleep you’ve experienced, you’ll probably be way out in your estimation. 

Penny Albright
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