Is 6 Hours of Sleep Enough to Function the Next Day? We Asked the Pros

In recent years, sleep has become the end-all, be-all of the health and wellness communities. All kinds of tools and products now exist to help us sleep, from fancy eye masks to scientist-approved mattresses. Yet despite all of this, data from the Centers for Disease Control and Prevention (CDC) suggests that about one in four American adults sleep less than seven hours a night on average—which is less than the recommended amount most experts say is essential for health and well-being.

But is it really the end of the world to snooze less than that? Is six hours of sleep enough for some of us? After all, the new parents and shift workers among us can attest that sometimes, it’s simply impossible to get that optimal seven to nine hours a night. We asked sleep experts to take us through the science about getting “enough” sleep, and why that looks a little different for everyone. 

Why Getting Enough Sleep Is Important

Consistently getting enough sleep is crucial. “Quality sleep impacts every area of your overall health, including cognitive/brain health, mental/emotional health, as well as physical and hormone health,” says Sarah Silverman, PsyD, a psychologist and behavioral sleep medicine specialist.

“Important processes are thought to occur during sleep,” adds Haunani ‘Iao, PsyD, a licensed clinical psychologist and the owner and CEO of ‘Iao Mind & Body Health. Those processes include tissue growth and restoration, memory reconsolidation, mood regulation, immune system augmentation, and much more. (Quite a bit happens when we’re in dreamland!)

The definition of “enough” sleep varies from person to person, both experts say. This is called “sleep need,” and essentially refers to how many hours of sleep a person requires to feel rested and functional during the day, ‘Iao says. She adds that these needs are genetically predetermined and decrease as we age. 

Is Six Hours of Sleep Enough? 

For some people, six hours of sleep might be enough to feel rested; for others, six hours might not even come close to cutting it. “Sleep is just like shoe size; one size does not fit all,” Silverman says.

The National Institutes of Health and the American Academy of Sleep Medicine recommend adults get at least seven hours of sleep a night. But not everyone needs that much, and some people need more, both experts say. “Anywhere from five to 11 hours may be appropriate for some adults, as per the National Sleep Foundation,” Silverman points out. (Again, it largely depends on your age and genes.)

Silverman suggests thinking of sleep needs on a bell curve (like an upside-down U). Some people will fall on the lower end of sleep need and will be totally fine and refreshed with just five or six hours of sleep. Others will fall on the higher end of sleep need and require nine hours to feel like a human. “Then the majority of the population will fall somewhere in the middle of the curve,” she says. 

“Although on the rare side, there are some individuals who have a genetic mutation for being more of a short sleeper,” Silverman adds, “and short sleepers typically do well with less than six hours of sleep.” 

However, if you tend to feel your best after seven hours of sleep or more (as many of us do), then six hours of sleep likely won’t cut it.

Consequences of Only Getting Six Hours of Sleep

If you’re a person who needs seven or more hours of sleep to feel refreshed and recharged, then getting only six hours of sleep a night could present some negative effects in the short and long term: 

1. You Might Feel Groggy or Slow 

Getting one less hour of sleep than you need can temporarily affect your cognition, Silverman says. “This could potentially impact next-day decision-making, ability to concentrate, focus, pay attention, as well as impact the ability to learn and remember things,” she says. These effects can get worse the more nights without enough sleep you get.

2. You Might Be More Grouchy or Anxious

Silverman says that not getting enough sleep can also have a big impact on your mood, making you feel more irritable or anxious. One 2018 review of studies suggests that sleep deprivation is associated with increased feelings of anger and aggression. And a large 2023 review looking at 50 years of data found that sleep loss was associated with more feelings of anxiety and “emotional numbness” and fewer positive emotions like happiness. 

3. You Might Be More at Risk of Car Accidents

Since sleep deprivation has been associated with impaired cognitive function, it makes sense that people might struggle to do everyday tasks like driving when they haven’t had enough rest. 

Silverman says that data from the AAA Foundation found that missing just one to two hours of sleep doubles a person’s risk of getting in a car crash. Those risks continue to increase with the more sleep you skip out on. Another study published in 2018 found that sleeping for six hours a night was associated with a notable increase (33 percent) in car crash risk compared with sleeping for seven or eight hours. 

4. You Might Develop Insomnia Over Time

Not getting enough sleep every so often is normal and not the end of the world, Silverman and ‘Iao agree. But over time, consistently getting just six hours of sleep when you really need seven or eight can have long-term consequences. “These types of changes [to sleep] and stressors can lead to insomnia—difficulty falling asleep, staying asleep, and waking up too early—even when there is a wider window of sleep opportunity available,” ‘Iao says. 

5. You May Have a Higher Risk for Various Health Conditions

Again, not getting enough sleep every so often is normal and not a huge deal for your long-term health. But if you’re consistently getting less rest than you need, research suggests you’re at an increased risk for some more serious health conditions, including dementia, diabetes, stroke, and heart attack. 

But before you start panicking, Silverman says that most of these kinds of studies are correlational, meaning they’re looking at associations (one thing linked to another in some way) rather than definitively proving cause and effect. “I think it’s fair to say that sleep scientists still don’t know what the ideal amount of sleep is… and are unsure about the optimal amount of sleep for long-term health implications,” she says. 

What If You Feel Fine with Six Hours of Sleep (or Can’t Get More Than That)?

Sleeping six hours a night is not inherently bad for everyone. If you feel well-rested during the day and not sleepy at any point after you wake up with just six hours of sleep, then you’re probably fine, Silverman says. (And personally, I’m jealous.) 

“I think it’s also important to note that shorter sleep does not imply a shorter lifespan,” Silverman says. She points out that while research has shown that people who usually sleep seven hours at night have the highest longevity, mortality at five hours of sleep per night is “basically the same” as mortality at eight hours of sleep. 

But if you experience daytime sleepiness—as in, you’re able to nap for several hours and/or doze off while sitting or being sedentary—that’s a sign that you’re not getting enough sleep or potentially have an untreated sleep disorder, Silverman says. 

What If You Can’t Get More Than Six Hours of Sleep?

From time to time, we intentionally choose to get less sleep than we need, like pulling an all-nighter to study for an exam or staying up way too late to catch up on House of the Dragon. But for some of us—particularly new parents and night shift or healthcare workers—getting enough sleep isn’t a reliably accessible option. In those cases, Silverman says there are a few ways to support rest and mitigate some of the impacts of sleep deprivation. 

“With opportunity, power naps—20–30 minutes—may be refreshing,” Silverman says. Just don’t make the nap too long, as long naps “often lead to feeling more grogginess during the day and may potentially impact the following night of sleep,” she says. If you’re a new parent, “it also helps, if possible, to alternate nights or shifts with your partner or another caregiver to ensure each parent gets larger blocks of uninterrupted sleep,” she adds.

Silverman also recommends being mindful of screen use at night if you’re struggling with sleep deprivation. “I tend to see a lot of moms who may wake up during the night to breastfeed and simultaneously check or scroll their phones,” she says by way of example. This can be very stimulating to your brain, not only due to the blue light exposure but also due to the content, which might make you worried or stressed—and hinder your ability to fall back asleep. 

Tucking away seemingly small chunks of time in the name of rest can help, too. “I often recommend prioritizing sleep over other tasks, especially non-essential tasks,” Silverman adds. “Use grocery and food delivery services, cleaning shortcuts, and other time-saving strategies to free up more time for rest, and ultimately, prioritize sleep whenever possible.”

6 Ways to Get More (and Better) Sleep

Sometimes we just don’t get enough rest, and it’s a flat-out bummer. To reduce the risk of that, Silverman and ‘Iao share some tips to help you sleep longer (and better): 

1. Create a Calming Bedtime Routine

Silverman says having a “buffer zone” before bed to unwind can help your body transition into sleep mode. This could look like stretching, meditating, or reading an enjoyable book, for instance. “Aim for at least 30–60 minutes before bed, or whatever time frame is realistic for you to stick to on a regular basis,” she advises.

2. Set a Regular Sleep Schedule and Be Consistent with It

“Set a sleep schedule that appears to fit your sleep need,” ‘Iao says. If you’re a person who needs seven hours of sleep to feel human, for example, you might set a bedtime of 11 PM and a wake-up time of 6 AM. “Get out of bed at the same time every day (even on weekends) and don’t linger in bed,” she recommends. “This will increase your sleep drive, which helps you to fall asleep and stay asleep all the way until your wake time.” 

If your current sleep schedule is way off from what you think it probably should be, Silverman suggests making small tweaks rather than changing it all at once. “If you need to adjust your sleep schedule, or you’re trying to shift your bedtime earlier, do it in small increments—15 minutes earlier every few nights—to allow your body time to adjust each night until you reach your desired bedtime,” she says.

3. Optimize Your Room for Sleep

“Only use your bed and bedroom for sleep and sex,” ‘Iao advises. Your bedroom should also be set up to promote sleep: dark, quiet, cool, and comfortable, Silverman adds. This will help you fall and stay asleep. 

4. Make Time for Self-Care Before Bedtime

Silverman’s hypothesis on why so many of us fall short on sleep is fairly simple (and sadly relatable): Many of us don’t feel like we have enough time in the day for self-care. So instead of getting ready for bed when the time comes, many of us stay up later to chill on the couch, watch TV, or do things for ourselves that we otherwise wouldn’t be able to fit into our days. (It’s something called revenge bedtime procrastination.)

If that sounds like you, “give yourself permission to have some extra ‘me time,’ but also ensure that you set a boundary and have a hard cut-off time—for example, 30 minutes before bedtime—so your behaviors before bed don’t lead to another night of sleep deprivation,” Silverman says. 

5. Be Mindful of What You Eat and Drink Before Bed

What you consume before bed can impact your ability to fall or stay asleep, both experts say. “Avoid heavy meals before bedtime and limit caffeine and sugar intake, especially later in the day,” Silverman recommends. “Stay hydrated, but try to limit fluid intake right before bed to avoid waking up for bathroom trips.” 

‘Iao adds that you should avoid drinking alcohol within two hours before bed. While booze can make you drowsy, “once the effects of alcohol are processed by your liver, your brain and body will awaken, and you will have difficulty falling back asleep,” she says. 

6. Talk to a Sleep Specialist

Untreated sleep disorders such as sleep apnea or restless legs syndrome can impact your ability to get enough sleep, Silverman says. She suggests seeing a sleep specialist if you snore, grind or clench your teeth, wake up with morning headaches, wake up multiple times during the night, or use the bathroom several times during the night. 

“These are all signs that you may have an underlying sleep-disordered breathing problem, and it’s worth looking into so you can get both the quantity and quality of sleep that your body needs to function optimally and feel well-rested during the day,” Silverman says. 

The Takeaway

Some people might feel great with just six hours of sleep, but it’s not the optimal amount for everyone—and not getting enough sleep at night can make the next day more difficult and unpleasant. Prioritize consistency as much as you can with your sleep schedule, and give yourself breaks where you can if your schedule is out of your control. “And when sleep deprivation becomes overwhelming, talk to your doctor or seek out a sleep specialist for professional help and support,” Silverman says.

This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.