Light sleep often gets dismissed in the context of evaluating sleep quality or a “good night’s sleep”, as it is seen as the significantly “lesser sleep” compared to the REM stage and the deep sleep stage.
However, light sleep is still an important stage of sleep with physiological benefits. But, what exactly is light sleep, and how much light sleep do you need per night compared to the different stages?
Light sleep will typically be around 60% of the overall sleep for a younger adult and increases as we age.
In this sleep needs guide, we spoke to three sleep experts to get their insight into how light sleep works and the breakdown of how much light sleep you need.
We will look at:
Let’s jump in!
What Are the Different Phases of Sleep In the Sleep Cycle?
Bianca Grover, an Exercise Physiologist, Medical Exercise Specialist, Health Coach, and Owner of Bianca Grover Fitness,1Bianca Grover Fitness. (2023, December 29). Bianca Grover Fitness. https://www.biancagroverfitness.com/ says that our sleep cycles are broken into two main categories, Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM).2Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., LaMantia, A.-S., McNamara, J. O., & S Mark Williams. (2001). Stages of Sleep. Nih.gov; Sinauer Associates. https://www.ncbi.nlm.nih.gov/books/NBK10996/
“However, we can break NREM down even further—into three stages that reflect how deep the sleep is,” explains Grover.
“These stages are N1 (Light Sleep), N2 (Deeper Light Sleep), and N3 (Deepest Non-Rem Sleep). On average, about 75% of sleep is spent in these NREM stages.”
What Is Light Sleep?
Susan Miller, a Certified Sleep Technician, Registered Polysomnographic Technologist™ (RPSGT),3About the RPSGT Credential – Board of Registered Polysomnographic Technologists. (n.d.). https://www.brpt.org/rpsgt/about-the-rpsgt-credential/ and Founder of Sleep Mattress HQ, 4Our Founder & Sleep Expert Susan Miller. (n.d.). Sleep Mattress HQ. Retrieved January 8, 2024, from https://www.sleepmattresshq.com/about/ says that light sleep occurs in the initial stages of Non-Rapid Eye Movement sleep (NREM sleep) and is characterized by a state of sleep from which you can be easily woken up.
“During this phase, you’re somewhat aware of your surroundings, but not as deeply as in the deeper sleep stages. It’s characterized by reduced muscle activity and slower brain waves compared to wakefulness,” says Miller.
“While external stimuli may disturb light sleep, they still serve essential functions, such as memory consolidation and overall mental recovery.”
So, how “light“ is light sleep? In other words, are you aware of your surroundings?
“During N1 (Light Sleep), you still may be aware of some things happening around you. This is why it is easiest to be woken by noise, light, and other disturbances,” explains Grover. “Once your body enters N2, it is less likely to be impacted.”
Dan Ford, a Sleep Psychologist and Founder of The Better Sleep Clinic, says that people sometimes barely perceive themselves as actually being asleep in the initial stages of light sleep.5Sleep Clinic NZ Insomnia Therapy Specialists | The Better Sleep Clinic. (n.d.). The Better Sleep Clinic | Auckland Sleep Medicine | NZ Insomnia Clinic. https://thebettersleepclinic.com/
“Stage 1 is very light, and people often perceive themselves as being awake. Stage 2 is better characterized as intermediate sleep, and levels of consciousness are relatively low,” explains Ford.
“However, it is still relatively easy to wake people from this stage. Studies show that, if woken, normal sleepers will perceive themselves as having been asleep during this stage, [but] people with insomnia will often perceive themselves as having been already awake.”
Is Light Sleep Restorative?
Grover says that light sleep plays an extremely important role in setting us up for the night of deeper and more restorative sleep cycles and locking in what we have learned through the day.
“To start, it helps prepare our body for a good night of rest by lowering our core body temperature, relaxing our muscles, and slowing down our brain waves,” explains Grover.
“In fact, you can aid in this process by taking a hot shower or bath before bed. Again, slightly counterintuitive, but a hot shower on the outside forces our body to cool itself on the inside. This also helps relax the muscles and put your mind at ease from the busy day.”
Not only does light sleep help guide your body and mind into the deeper stages of sleep, but it also helps establish memories in your “memory bank.“
“In addition to preparing our bodies for the night ahead, light sleep also helps to lock in our experiences from the day we have just finished,” notes Grover. “This is the most important time for us to lock in memories, and it aids in the development of motor skills.”
Miller wholeheartedly agrees that light sleep is still restorative and explains that there are many light sleep benefits.
“Light sleep serves a vital role in the sleep cycle and contributes to overall restoration,” she shared.
“It aids memory consolidation, supports cognitive functions, and allows the body to gradually transition between the wakefulness and deep sleep stages. Light sleep is essential for maintaining a healthy sleep architecture.”
Ford agrees that light sleep, particularly stage 2 light sleep, is still restorative for the body.
He notes:
“Stage 2 sleep is less studied than other stages, but given that you spend the bulk of the night in this stage and there are a mixture of brainwaves, including those characteristic of deep sleep, it is likely to be important for restoration and will be carrying out some of the functions of stage 3 deep sleep.”
How Much Light Sleep Do You Need Per Night?
So, how much light sleep is normal?
“The ideal amount of light sleep varies, but on average, adults may spend around 50-60% of their night in various sleep cycles, including light sleep,” shares Miller.
“However, age and sex can influence sleep architecture. Generally, as people age, the proportion of time spent in deep sleep decreases, and the lighter sleep stages may increase.”
Ford agrees that light sleep will typically be around 60% of the night for a younger adult and increases as we age, but adds an important detail that may largely explain why we see this relative increase in light sleep and decrease in deeper sleep across the lifespan:
“Your body will give you as much as you need in relation to your daytime activity,” shares Ford.
Because physical activity levels tend to decline with age, the amount of sleep that we need per night may decrease as a result.
Grover provides a more specific breakdown of how much light sleep is normal based on each stage of light sleep.
So, what percentage of sleep should be light sleep?
She says the N1 light sleep is about 5% of our sleep. So your total sleep time is 8 hours, the N1 light sleep stage is roughly 24 minutes.
N2 light sleep is typically the sleep phase where adults spend the greatest amount of time relative to the other stages of sleep. Grover says the N2 stage of sleep usually constitutes about 45% of our sleep time, just over 3 1/2 hours of sleep of an 8-hour sleep duration.
Does the Amount of Light Sleep We Get Per Night Change With Age or Sex?
“As we age, it is normal for the amount of light sleep we experience to increase,” suggests Grover, who explains that this might be intuitive because older adults tend to wake up more easily in the middle of the night.
“Older adults tend to wake up in the middle of the night, but consider that waking up in the middle of the night may be a result of this increased time in the light sleeping stage,” she notes. “After all, this is when it is easiest to be woken from sleep.”
As a result, because the amount of light sleep tends to increase for older adults, seniors see a resultant decrease in the amount of deep sleep and REM sleep per night.
Note that the increase in light sleep and decrease in deep sleep that accompany aging are generalizations and will not apply to every older adult vs younger adult.
Moreover, when we talk about getting more light sleep as you age and less deep sleep per night as you age, we are discussing the relative percentage of time spent in each sleep stage.
On average, older adults tend to sleep fewer hours per night than younger adults.
Therefore, even if an older adult is getting more light sleep than a younger adult, because the older adult probably has a shorter sleep duration in total, the number of minutes in light sleep might be the same between the younger and older adult.
For example, if a younger adult sleeps eight hours and spends 60% of the sleep cycle in light sleep, he or she gets 4.8 hours of light sleep.
If a senior sleeps seven hours per night, of which 70% of the sleep cycle duration is light sleep, he or she is getting a similar 4.9 hours of light sleep.
According to Grover, “In general, we do not see noticeable or consistent differences in light sleep duration between men and women, but rather, variations are unique to the individual and their sleep habits.”
Remember: even though we tend to consider light sleep as the “lesser sleep“ or not as beneficial as deep sleep and REM sleep, light sleep still provides numerous benefits.
Are you interested in the other sleep stages and if you are getting enough sleep, such as how much deep sleep or how much REM sleep you should get per night? If so, check out:
