How Much Sleep Do We Really Need?

Out of the three pillars of health, sleep seems to be the one most people are willing to give up in the name of productivity or entertainment. (5) But if there’s one thing most sleep experts can agree on, it’s that sleep isn’t really negotiable. Time and again, research has shown us just as much — failure to log enough shut-eye over a long period has far-reaching consequences ranging from moodiness and irritability to high blood pressure and heart disease. (6) So, how much sleep do we need? Well, that depends.

Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t be taken as medical advice, and it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.

How Much Sleep Do You Need?

Though many of us have heard that 7-9 hours of sleep per night is the sweet spot, that recommendation varies by age.

How Much Sleep Do You Need by Age

Try as you might; you’d be hard-pressed to find a one-and-done prescription for how much sleep you need. However, if you’re looking for a jumping-off point, the American Academy of Sleep Medicine (AASM) outlines the following sleep recommendations by age range. (1)

• Infants (4 months to 12 months) 12 – 16 hours (including naps)
• Toddlers (1 to 2 years of age) 11 – 14 hours (including naps)
• Preschoolers (3 to 5 years of age)  10 – 13 hours (including naps)
• School Age Kids/Tweens (6 to 12 years of age)  9 – 12 hours
• Teens (13 to 17 years of age)  8 – 10 hours
• Adults (18 years and older) 7 or more hours

Again, these are only guidelines and sleep recommendations vary by institution or organization. The fact is your sleep needs may vary throughout your lifetime based on a host of factors, including your age, lifestyle, and general health. 

Factors That Influence How Much Sleep You Need

Besides age, overall health, genetics, and even the room you sleep in can all affect how much sleep you need throughout your life. 

Pregnancy and Sleep

Problems like insomnia and restless leg syndrome are quite common during pregnancy. (7) Throw in fluctuating hormones and the physical discomfort of a growing belly, and you can see why sleep really takes a hit in terms of duration and quality among people who are pregnant. These factors can lead to overall sleep loss, fatigue, and daytime sleepiness, ultimately bumping up a person’s need for sleep. (8)

Genetics and Sleep

Believe it or not, your genetics may impact how much sleep you need as well as your sleep patterns. (9) Not only has research shown that sleep duration and quality may be heritable traits, but your genes can also dictate your chronotype (your preference for staying up late or waking early). (10) Night owls and early birds, you can likely thank your parents. Genetics also influences your likelihood of developing sleep disorders like insomnia and sleep apnea, both of which can affect the amount and quality of sleep people get. (11) (12)

Illness and Sleep

When you’re sick with the flu or common cold, the exhaustion and fatigue accompanying those illnesses may be a sign that you should double down on your rest time. And make no mistake: You may be out for the count, but when you’re snoozing, your body is hard at work fighting your illness courtesy of cytokines (your body’s immune system response to help fight inflammation and infection) that help promote sleep.  (13)

But it doesn’t end there — research has also shown that sleeping while sick can offer another assist to your army of cytokines. This one comes courtesy of T cells, a type of white blood cell, that’s part of your immune system. Not only does a restful night’s sleep help T cell production and activity, but deep sleep (or slow-wave sleep) helps T cells move toward lymph nodes, further stimulating an immune response. (14)

Sleep Disorders

“Sleep disorders can cause an overall deficit in the amount of rest one gets,” says psychiatrist Sham Singh, M.D. More specifically, he explains that sleep disorders like insomnia, sleep apnea, or restless leg syndrome can prevent a person from falling asleep easily or cause frequent nighttime waking, either (or both) of which can lead to short sleep. (15)

Sleep disorders can also affect sleep quality. “Even if the person is in bed for an adequate amount of time, they might not reach the deeper, more restorative stages of sleep needed for optimal health,” says Singh. He explains that sleep disorders create a gap between the sleep we need and the actual amount we get each night. Ultimately, this leads to chronic sleep deprivation, which in turn exacerbates the symptoms of the disorder, thus creating a cycle. 

Poor Sleep Quality

The quality of sleep you get each night can significantly impact the amount of sleep you need. For example, if your sleep consistently falls short due to a sleep disorder, like obstructive sleep apnea or restless leg syndrome, you may need to make up for lost or poor-quality sleep — often called sleep debt — to feel rested and restored. (16) If you’re wondering just how much catching up you need to do, check out our sleep debt calculator.

Sleep Environment

And finally, your environment can play a crucial role in determining your sleep needs. Those failing to mitigate noise and light disturbances may be more likely to have poor quality sleep and may eventually require more sleep to make up for their lack of sleep quality night after night.  (17)

Why is Sleep Important?

Acting as a foundation for overall well-being, sleep plays a vital role in our physical and mental health. Not only is sleep a crucial part of the body’s growth and repair processes, but it can also have a profound effect on cognitive function and emotion regulation. (18)

The physical benefits of quality sleep can include: (19) (20)

• Growth hormone release (which supports muscle growth, tissue repair, and protein synthesis)
• Healthy immune function 
• Hormone regulation (cortisol and insulin)
• Improved heart health 

The mental benefits of quality sleep may include: (21) 

• Stress reduction 
• Enhanced mood 
• Memory consolidation support 
• Enhanced learning, problem-solving 

What Happens When You Don’t Get Enough Sleep 

The fact that most adults need at least 7 hours of sleep each night is almost common knowledge, yet research shows that well over 30 percent of US adults get fewer than seven hours of sleep each night. (2) The problem arises when short sleep becomes the rule rather than the exception. A restless night here and there is usually no cause for concern, but prolonged bouts of sleep deprivation may register on your physical and mental health. 

Effects of short-term sleep deprivation may include: (22)

• Headaches
• Excessive daytime sleepiness/fatigue 
• Moodiness/Irritability
• Poor focus/concentration
• Impaired memory 
• Delayed reaction times 

Effects of long-term sleep deprivation and sleep disorders may include increased risk of: (22)

• Impaired cognitive function 
• Type 2 diabetes (23)
• Obesity
• Stroke
• Cardiovascular disease
• Heart attack 
• Depression
• Anxiety 

What is the Minimum Hours of Sleep I Can Get?

Most sleep experts agree that adults should aim for at least 7 hours of sleep each night for optimum health and functioning. (1) This timeline typically allows for ample time in each sleep stage. This is particularly important for deep sleep and REM sleep stages, which do the heavy lifting for physical and mental restoration. (24)

For those who can’t hit that minimum (due to responsibilities and scheduling obligations), Singh says, “Getting the best quality sleep out of the sleep they can get is important.” And while he notes that naps can be helpful, he cautions nappers to mind the timing and duration. “A 20-30 minute nap can enhance alertness and performance without the groggy feeling, but take care not to nap too close to bedtime since this may hamper your night-time sleep.” (25)

Tips for Better Sleep

Better sleep often begins with sleep hygiene. While there has always been a lot of chatter — and maybe even some confusion about it — Robert T. Knight, professor of psychology and neuroscience at the University of California, Berkeley, and Co-Founder of Somnee says, “There is no magic to sleep hygiene; a lot of it is common sense.” 

To improve the quantity and quality of your sleep, sleep hygiene best practices include: (26)

• Maintaining a consistent sleep-wake schedule  
• Ensuring sure your sleep environment is quiet, cool, and dark. 
• Avoiding heavy meals before bed
• Managing your exposure to blue light in the evening, and don’t bring electronic devices into the bedroom
• Avoiding stimulants and caffeine in the late afternoon and evening
• Reserving your bed for sleep and sex, only
• Establishing and maintaining a soothing bedtime routine that includes relaxing wind-down activities like reading a book, listening to soft music, or a warm bath.

How Do I Know If I’m Getting Enough Sleep?

For those concerned about not logging enough shuteye, Knight says keeping tabs on your sleep is as easy as assessing how you feel. 

The TLDR: “ If you wake up refreshed, you’re getting enough sleep,” he says. 

Other signs and symptoms of insufficient sleep may include: (6)

• Poor concentration
• Impaired memory, performance, and productivity
• Moodiness and irritability
• Slower reaction times
• Impaired problem-solving skills

Knight adds, “A night or two of disrupted sleep is normal. There’s no magic number, but after a week to ten days of disrupted sleep, it may be time to reevaluate your lifestyle.” We’ll add here that prolonged bouts of poor or insufficient sleep may also be a sign of something more serious, and you should probably speak with your doctor. 

Can I Sleep Too Much?

Keeping it short and sweet, Knight simply says, “No,” you can’t sleep too much. While everyone requires a different amount of sleep for normal functioning, most healthy people can’t and won’t “overdose” on sleep. 

Existing research corroborates as much. A 2021 study revealed that oversleeping, or long sleep episodes, are often just temporary, as we’re just not programmed to sleep more than is biologically necessary. (27) Incidentally, the same study demonstrated that we have a “homeostatic set-point” for sleep. The research study findings suggest that “the average healthy young human can not chronically sleep over 10 [hours] per day: the average sleep duration was 8.6 [hours]. (27)

Now, just because you can’t technically oversleep doesn’t mean that some people don’t sleep longer than they should. If you find that you are sleeping longer, you may want to keep a sleep diary for a week or two and speak with your doctor. Sleeping longer than usual may be a sign of an underlying health condition, and continually doing so can lead to fatigue and a circadian rhythm that’s thrown out of whack.

FAQs

The Last Word From Sleepopolis

Sleep plays a crucial role in our overall health and wellness. By understanding how much sleep we need, prioritizing quality rest, and practicing good sleep hygiene, we can improve our chances of getting adequate, good-quality sleep night after night.

Sources

Sharon Brandwein

Sharon Brandwein is a Certified Sleep Science Coach and a freelance writer. She specializes in health and beauty, parenting, and of course, all things sleep. Sharon’s work has also appeared on ABC News, USAToday, and Forbes. When she’s not busy writing, you might find her somewhere curating a wardrobe for her puppy.