Last Updated on February 12, 2024 by Louise Carter
Time perception during sleep often seems different from that of our waking hours.
Sleep experts recommend getting at least 8 hours of rest a night, and a typical working day lasts 8 hours. However, our time in bed sleeping seems to move much faster.
Time moves at the same rate, regardless of whether we’re awake or asleep.
The third of the four sleep stages is called slow-wave sleep. During this stage, we have little brain activity. This disengagement from thought processes and consciousness means time seems to race by.
If you wake up groggy or unrested in the morning, it doesn’t mean time moved differently while asleep. Your sleep cycles influence your perception of time.
Does Time Move Differently When We Sleep?
Time is linear. If you run a stopwatch for 1 minute, those 60 seconds will run for the same time, whether you’re awake or asleep. If you doze off for that minute, the time will pass in the blink of an eye.
We’re relaxed and not paying attention to our surroundings when we sleep. As a result, time seems to pass faster. However, if you know you’re being timed, you’ll likely feel every moment passing.
Part of this is down to relativity, allegedly summarized with a famous quote:
“When you sit with a nice girl for 2 hours you think it’s only 1 minute, but when you sit on a hot stove for 1 minute you think it’s 2 hours. That’s relativity.”
Albert Einstein
If you go to bed at 11 PM and fall asleep instantly, the next time you glance at your clock, it may be 3 AM or 4 AM. If you’re lucky, you won’t even need to recheck the time until morning.
Insomnia has struck if you can’t sleep, and time will likely feel very different.
Lying in bed with your eyes closed and growing increasingly frustrated at being awake, you may think that hours have passed, and in reality, it’ll only be 11.30 PM.
Understanding that time doesn’t move faster while we sleep is essential. All the same, we can use sleep to pass the time and bring about a rapid transition into a new hour or day.
Why Does Sleep Feel So Short?
Sleep seems to make time move faster, which many of us learn as children. When we have something to look forward to, going to bed early seems to bring about the next day sooner.
Think of a good night’s sleep as akin to an operation that requires a general anesthetic.
When we’re in the OR and feeling the effects of the sedative, our eyes will close, no matter how much we fight it. The next thing we know, we’re awake and in the recovery ward.
We could have been under the influence of anesthesia for just 30 minutes or as long as 10 hours. The outcome is the same: we won’t remember or notice that we were asleep during the procedure.
The same applies when we fall into a deep and restful sleep at night.
If we sleep the entire night, not needing to use the bathroom overnight or rise for any other reason, the distance between bedtime and the sound of an alarm can feel like seconds.
Not all sleep stages appear to speed up time in this fashion.
Slow-wave sleep is the most critical component to making sleep feel like a way to speed up time. This is one of the 4 stages of sleep that we all go through each night in bed.
What Are The Four Stages of Sleep?
Whenever we sleep, the body and brain cycle through four disparate stages, which are as follows:
| Stage 1: | This is the first few moments after you close your eyes. You can be roused from sleep by the slightest noise or nudge and may experience involuntary muscle twitches and jerks. |
| Stage 2: | You start to fall into a deeper sleep. Your heart rate slows, your body temperature cools a little, and your thought processes are much less active. |
| Stage 3: | Also known as slow-wave sleep, your brain is wholly disengaged while your body repairs damage and wear and tear. This is the deepest sleep we experience. |
| Stage 4: | REM sleep is when the brain re-engages, and you experience dreams. Time feels longer at this point of sleep, especially compared to stages 3 and 4. |
These stages will repeat multiple times throughout your time in bed, and each is equally important. The third stage is what governs our perception of time while we sleep.
What Is Slow-Wave Sleep?
Slow-wave sleep, called deep sleep, could be considered downtime for the brain.
This stage of sleep, which sees the brain release delta waves, is preparation for the final stage of sleep to follow – rapid eye movement (REM) sleep.
The Journal of Clinical Sleep Medicine explains that slow-wave sleep is the most critical sleep stage. Deep sleep allows the body to relax and repair itself, improving the chances of feeling refreshed in the morning.
Think of slow-wave sleep as an opportunity to recharge your batteries. Your cellphone will cease working if you don’t place it on charge overnight, and the same applies to the human body and brain.
Why Does Slow-Wave Sleep Impact Our Sense of Time?
Time lacks meaning if you’re disengaged from the world around you. If you’re focused on something, seconds feel like they drag. Examples can be found in many walks of life, not just in sleep.
Picture any of the following scenarios:
- You walk into a movie theater at 7 PM when it’s light and leave at 10.30 PM when it’s dark. You were engaged in watching the movie, so you didn’t notice the time pass.
- You practice meditation or other acts of mindfulness. During this time, you’re disengaging your mind in its entirety. According to Consciousness and Cognition, this alters your perception of time.
- You’re busy at work, barely having time to stop and drink a coffee or use the bathroom between tasks. Before you know it, your shift is over, even though it feels like you’ve just started.
Whatever you do to pass the time, you’ll cease to watch the clock. This will make time appear to move faster, while the opposite is also true. As the popular adage claims, “A watched pot never boils.”
Does Sleep Feel Longer When We Dream?
Having established that slow-wave sleep is the third stage of our sleep cycle, REM sleep is the final stage. REM sleep is where we dream, and the body cycles in and out of REM throughout our time in bed.
The American Journal of Physiology explains that REM sleep varies in length. Your first cycle is likely to be as short as 10 minutes, but when the body is in its final REM stage, it could last as long as 1 hour.
It’s believed that humans dream in slow motion. Explanations vary, although the most common reason is that the brain continues to work slowly while in REM sleep.
We’re still asleep, but our perception of time shifts. While we undergo REM sleep and dream, rest can feel longer, especially if we recall our dreams in the morning. A vivid dream can feel like it lasted hours.
This may contribute to waking up feeling unrested despite sleeping for 8 hours. If you had a series of nightmares during your REM sleep cycle, you wouldn’t have enjoyed much quality sleep.
Equally, you may have dreamt about physical activity. Suppose you dreamt about running a marathon. You may have kicked your legs in your sleep and feel the physical after-effects in the morning.
Unfortunately, you won’t automatically enjoy the endorphins that accompany exercise, as you’ll need to stretch for that to happen. Whether you recall 5 dreams or none, time moved at the same pace.
Going to bed early can bring about a new day much faster. It depends on whether you enjoyed enough restful sleep and what sleep stages dominate your time in bed.
An hour of sleep or an hour awake both contain 60 minutes, regardless of how it feels.
