Is 6 Hours of Sleep Enough? 5 Reasons Why It’s Not

Your true sleep need, daytime drowsiness, ineffective sleep hacks, subjective adaptations, and pseudo productivity are proof that 6 hours of sleep isn’t enough.
Man sleeping at desk in office feeling sleepy after 6 hours of sleep

Did you know that there are only three genes that let you sleep 4-6 hours and still feel in top form the next day?

Scientists at the University of California, San Francisco (UCSF) discovered that the NPSR1 gene mutation allows you to get by on 4-5.5 hours of sleep, with the added bonus of warding off memory problems associated with sleep deprivation. Similarly, those with the DEC2 and ADRB1 gene mutations need only 5-6 hours per night.

The catch: Only an infinitesimal minority are blessed with the short-sleep genetic material. And, what’s more, just because you have one of these mutations doesn’t mean you’re guaranteed to have short sleep.

As Dr. Thomas Roth says in Matthew Walker’s book, Why We Sleep, “The number of people who can survive on 5 hours of sleep or less without any impairment, expressed as a percent of the population, and rounded to a whole number, is zero.” Case in point: The UCSF researchers highlighted that the NPSR1 gene mutation “is exceedingly rare, occurring in fewer than one in 4 million people.”

That brings us to the question of today’s post, “Is 6 hours of sleep enough?” Unless you’re already biologically equipped with a genetic cheat sheet for short-sleeping - and the mutation is active -six hours of sleep just isn’t sufficient as you’ll see below.

1. Your Sleep Need Is Definitely More Than 6 Hours

To the masses, six hours of sleep seems to be a fairly reasonable amount to squeak by compared to four or five hours of sleep. After all, a quick Google search will show some sleep guidelines recommend getting around 6-8 or 6-7 hours of sleep per night.

Here’s the thing: You’re more likely to be struck by lightning than you are to possess the gene that allows you to sleep six hours a night with minimum ill effects.

According to science, the average sleep need stands at 8 hours and 40 minutes per night (plus or minus 10 minutes or so). What’s more, a not-insignificant percentage of the population (13.5%) may need a longer sleep schedule of nine hours or more.

As such, just meeting the bare minimum of the cookie-cutter generalization of 6-8 hours of sleep is likely not enough for meeting your individual sleep need. Unsurprisingly, many of us are then bogged down with sleep debt, the amount of sleep you’ve missed in the past 14 days relative to your sleep need.

To compound the issue of insufficient sleep because of an underestimated sleep need, we tend to overestimate our sleep duration. Between taking time to fall asleep and getting up in the middle of the night, time spent in bed is very rarely time spent asleep. So, if you only had six hours of sleep opportunity in bed, your actual sleep time is certainly less than that.

2. You Misread Daytime Drowsiness

You don’t need to be full-on snoring at your work desk to realize six hours of sleep isn’t cutting it for you. Simply experiencing mild daytime sleepiness is a sign that your body is already suffering from a lack of sleep.

As William Dement, one of the founders of the field of sleep medicine, often quoted, “Drowsiness is red alert.”

Other warning signals of sleep deprivation include nodding off the moment your head touches the pillow, the overwhelming urge to nap, and morning sleep inertia that seems longer and more intense than usual. (And, as we explain below, another way to “misread” daytime drowsiness is to think your perceived lack of daytime drowsiness means you’re adequately slept, when in fact you’ve subjectively adapted to sleep loss.)

3. You Can’t “Hack” Sleep

The human body is biologically built to get the sleep it needs in the form of sleep cycles.

Each sleep cycle consists of non-rapid eye movement (NREM) sleep and REM sleep. NREM sleep is further split into three stages of sleep, whereby stages 1 and 2 are light sleep while stage 3 is deep sleep.

Everyone cycles through all stages of sleep about 4-6 times per night, spending roughly 1.5 hours in each cycle. Once you do the math, you can see how it’s impossible to compress your individual sleep need into merely six hours (unless that’s your actual need).

Furthermore, science reveals that our sleep patterns change when we try to survive on less sleep than we need. One or more nights of sleep loss means the human brain retains deep sleep at the expense of stage 1, stage 2, and REM sleep. Before you assume this is a good thing, keep in mind that REM sleep is indispensable to emotional processing and regulation, learning and memory consolidation, as well as creative thinking and problem-solving.

Moreover, given how the brain cherry-picks specific sleep stages over others is evidence enough it naturally self-optimizes. That means you can’t consciously manipulate how much time to spend in a given stage of the sleep cycle (save for negatively influencing your sleep architecture via poor sleep hygiene), invalidating any “sleep hacks” you may have found on the Internet.

4. You Subjectively Adapt to Objective Downgrades

Perhaps the most insidious aspect of sleep loss is that we subjectively adapt to it. Studies repeatedly show that our perceived sleepiness increases following multiple nights of insufficient sleep only to plateau under conditions of continued sleep loss. Meanwhile, every aspect of our daytime functioning objectively downgrades the more sleep deprived we are.

This deception is further reinforced by our circadian rhythm (the internal body clock that dictates your energy peaks and dips), which operates independently of your sleep drive. So, even if you’ve under-slept your sleep need last night, the energy surge during your two daytime peaks can work to somewhat mask the effects of sleep deprivation. The downside is that your energy peaks could have soared higher if you had gotten enough shut-eye in the first place, and your dips will now feel much lower.

5. You Aren’t Productive With the Extra Hours of Wakefulness

Shortening your biological sleep need to only six hours of sleep may give you the illusion of a few extra hours of wakefulness to get more things done. But the truth is, you aren’t being as productive as you could be if you had enough sleep.

The resulting sleep debt has already taken a hammer to your daytime productivity and overall well-being, beating them into submission. Consequently, even the simplest task on your to-do list can feel like a Herculean effort, much less squeeze in demanding work obligations or break your PR in the gym.

The Fallout of Sleep Insufficiency in the Short and Long Term

So far, we’ve (hopefully) convinced you that six hours of sleep isn’t enough — unless you’re one of the aforementioned short sleepers by nature.

To make matters worse, your sleep problems also come with their own negative effects in the short and long term.

Acute Sleep Debt

Acute sleep debt (measured over a 14-day window) doesn’t simply stop you from feeling and functioning at your best the next day. To illustrate, pulling an all-nighter impairs your cognitive skills, akin to having a blood alcohol level (BAC) of 0.10%, higher than every state’s legal limit.

But you don’t have to stay up for 24 hours to feel these effects. Sleeping for only seven hours over 10 consecutive nights will make your brain as impaired as it would if you had not gone to bed last night, even though you may not feel that way when you wake up.

To give you more cause to meet your sleep need tonight, one study found that sleeping for only six hours or less means you’re four times more likely to catch a cold than if you had slept for seven hours or more.

Chronic Sleep Deprivation

When you give acute sleep debt a chance to roll over many months and years, it mutates into chronic sleep deprivation. Before you look upon it as a badge of honor in today’s hustle culture, you may want to be forewarned about its unwanted side effects first.

Chronic sleep deprivation brings about its own baggage, mainly physical and mental health issues.

Constantly under-sleeping your sleep need intensifies your risk of chronic medical conditions, such as type 2 diabetes, cardiovascular disease, and high blood pressure. It also induces weight gain (that may snowball into obesity) and weakens your immune system.

Stop Sleeping 6 Hours; Start Meeting Your Sleep Need

RISE app screenshot showing your sleep need so you can keep sleep debt low.
The RISE app shows your biological sleep need to help you keep your sleep debt low for better energy during the day.

It’s in your best interest to stop short-changing your life by only sleeping six hours each night. Instead, figure out why you’re not meeting your sleep need in the first place.

Perhaps a demanding work schedule is barring you from a good night’s sleep. Or maybe your newborn hasn’t gotten the sleep memo and often wakes up in the middle of the night. Your lack of sleep could also be due to an underlying medical condition. For example, various sleep disorders like obstructive sleep apnea, restless leg syndrome, and sleepwalking disrupt sleep. Not to mention, poor sleep hygiene is the proverbial kryptonite to meeting your sleep need.

This is where the RISE app can help.

RISE calculates your personal sleep need by using the sleep and activity data on your phone measured over the last 365 nights. It also reveals your running sleep debt on the Sleep tab to show if you’re getting too little sleep (aim for five or fewer hours of sleep debt).

But knowing your sleep need and current sleep debt isn’t enough — you need to be able to consistently meet your need to keep your debt low. This is where the app’s 20+ science-backed sleep habits help nudge you at the right time to be on the same wavelength as your circadian rhythm.

For example, adding the “Melatonin Window” habit to your Energy Schedule tells you the best time to go to bed for better sleep that night. Pair it with the “Evening Routine” habit to schedule your bedtime routine right before your Melatonin Window, so that you can segue into sleep and meet your need more effortlessly.

As you evolve from a 6-hours-a-night to your true sleep need, give yourself grace and time to make that transition. If you can, take daytime naps to pay down sleep debt. RISE tells you the exact window of your afternoon dip so you know when’s the best time to get some shut-eye.

Resetting your sleep schedule won’t be an overnight transformation, but the effort will be absolutely worth it. Download the RISE app today, so you can start feeling and functioning at your best.

How Much Sleep is Right For You?

Summary FAQs

Is 6 hours of sleep enough for one night?

For most of us, six hours of sleep is not enough for one night. Scientific evidence indicates the average sleep need is around 8 hours and 40 minutes per night (plus or minus 10 minutes or so), with 13.5% of us requiring nine hours or more of sleep time.

Is 6 hours of sleep enough for older adults?

6 hours of sleep is not enough for most older adults. A common misconception is we need less sleep as we age. Instead, the quality of your sleep declines with age. Older adults often unfortunately “get” less sleep, even though the amount of sleep they “need” hasn’t changed. Meeting your sleep need supports healthy adults at any age.

Is 6 hours of sleep enough for a kid?

6 hours of sleep is not enough for a kid. Nation Sleep Foundation guidelines suggest toddlers get 11-14 hours of sleep a night, preschoolers get 10-13 hours of sleep, and the school-age age group of 6-13 year olds get 9-11 hours of sleep per night.

Is 6 hours of sleep enough for a teenager?

Sleep boards such as the National Sleep Foundation and the American Academy of Sleep Medicine agree 6 hours of sleep is not enough for a teenager, as their guidelines suggest a longer sleep duration of 8-10 hours. This is in line with other research on the average sleep need for healthy young adults.

Is 6 hours of sleep enough for a student?

6 hours is almost certainly not enough sleep for a student. Sleeping less than you need often comes directly at the expense of REM sleep, which is a critical sleep stage for learning. Getting only 6 hours of sleep is very likely to undermine a student’s productivity and performance (not to mention their physical health).

Is 6 hours of sleep enough to build muscle?

Sleeping for merely six hours is a guaranteed recipe for sleep dept, unless six hours is your biological sleep need. Research shows that sleep deprivation, even for one night, is enough to reduce “muscle protein synthesis by 18%,” so you’re more likely to experience muscle loss than growth.

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About Rise
Rise is the only app that unlocks the real-world benefits of better sleep.

Instead of just promising a better night, we use 100 years of sleep science to help you pay down sleep debt and take advantage of your circadian rhythm to be your best.

Over the past decade, we've helped professional athletes, startups, and Fortune 500s improve their sleep to measurably win more in the real-world scenarios that matter most.

Rise Science is backed by True Ventures, Freestyle Capital, and High Alpha; investors behind category winners Fitbit, Peloton, and Salesforce Marketing Cloud.
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