If you find yourself asking, “How much sleep do I need?” you’re not alone. Between work, family, late-night scrolling and early morning alarms, getting enough rest can feel impossible. But sleep isn’t just about feeling less tired; it’s tied to everything from your mood and memory to your immune system and long-term health.
We spoke with sleep experts to find out how much sleep you need, how it changes as you age and how it can affect your health. “The key is to find out how much sleep you need to function well during the day, without relying on what sleep clinicians call ‘safety behaviors,’ such as caffeine to improve daytime alertness and/or using alcohol or other sleep aids to assist falling asleep at night,” says Michael Gradisar, head of sleep science at Sleep Cycle.
How much sleep do people really need?
The National Sleep Foundation, American Academy of Sleep Medicine and Sleep Research Society recommend adults get between 7 and 9 hours of sleep each night. “But it is important to understand that individual needs vary,” says Dr. Angela Holliday-Bell, sleep adviser at NextSense. “Sleep isn’t just about quantity -- quality and consistency also matter significantly.”
Keep in mind that seven to nine hours refers to actual sleep time, not just time spent in bed. If you're in bed for a total of eight hours but tossed and turned for an hour, that’s only seven hours of sleep.
You cycle through multiple sleep stages throughout the night, with about 75% spent in non-rapid eye movement sleep and the rest in rapid eye movement sleep. The cycles repeat about four to six times per night:
- N1: Light sleep -- The lightest stage of sleep, a transition between wakefulness and sleep.
- N2: Moderate sleep -- Heart rate and body temperature drop as the body prepares for deeper sleep.
- N3: Deep sleep -- Known as slow-wave sleep, this stage is the deepest, characterized by delta waves, and is the hardest to wake from, often causing grogginess if disturbed.
- N2 (again) -- You cycle back into this stage before entering REM sleep.
- REM: Rapid Eye Movement sleep -- Beta waves cause irregular and erratic breathing during the dream/nightmare stage, similar to brain waves when you’re awake.
However, sleep cycles don’t always follow a perfect sequence. Early in the night, N3 (deep sleep) dominates, while REM occurs in longer bursts later on. The exact percentage of each stage also varies by age and health.
Deep and REM sleep are critical stages, as your body and brain are actively working to restore function and keep you healthy.
How much deep sleep do you need?
“Deep Sleep is a crucial stage of sleep which is essential for several physical, emotional and cognitive restorative functions,” says Dr. Fouzia Siddiqui, neurologist and sleep center medical director at Sentara Health in Harrisonburg, Virginia. “During deep sleep, the body repairs and regenerates tissues, builds bones and muscles, and strengthens the immune system.”
She tells CNET that sleep also regulates growth hormones and metabolism, improving learning and memory creation. A 2025 study found that insufficient time spent in deep and REM sleep may be linked to cognitive decline, but more research is needed.
Deep sleep should make up roughly 25% of your sleep per night, which is around 1.5 to 2 hours.
How much REM sleep do you need?
REM sleep “stimulates the areas of your brain that are essential in learning and making or retaining memories,” says Lauri Leadley, founder and clinical sleep educator at Valley Sleep Center in Arizona. “During this cycle of sleep, your eyes will move and dart quickly beneath your eyelids, your brain activity increases, your pulse quickens and you have dreams.”
On average, it takes about 90 minutes to enter the REM stage after falling asleep. The first cycle lasts around 10 minutes, with each cycle increasing to about an hour in the last cycle of the night. However, factors such as stress, medication, alcohol, sleep deprivation and certain sleep disorders can impact the exact time we enter REM and the time spent in each sleep stage.
Like deep sleep, you should get about 25%, or approximately 1.5 to 2 hours, of REM sleep each night.
Sleep needs change over your lifespan
Our sleep needs change as we age. Newborns need up to 17 hours of sleep each day, while adults usually only need between 7 and 9. “Older people still require sleep but sometimes struggle to stay asleep. I notice this in many of my elderly patients with lung or heart conditions,” says Dr. Emma Lin, pulmonary and sleep medicine physician at ReadyO2.
Here are sleep recommendations by age group, including naps, according to the American Academy of Sleep Medicine:
- Newborns (0-3 months): 14 to 17 hours per day
- Infants (4-11 months): 12 to 16 hours per day
- Toddlers (1-2 years): 11 to 14 hours per day
- Preschoolers (3-5): 10 to 13 hours
- School-age children (6-12): Nine to 12 hours
- Teenagers (14-18): Eight to 10 hours
- Younger adults (19-25): Seven to nine hours
- Adults (26-64): Seven to nine hours
- Older adults (65 and older): Seven to eight hours
Note: These are general guidelines. We are all different and have different sleep needs. Some may do well with six hours of sleep, while others may need nine.
Other factors that affect how much sleep you need
“Unlike ‘sleep duration,’ ‘sleep need’ has not been studied sufficiently enough for us to understand all the different factors that may influence it,” Gradisar said. “Sleep need often refers to the amount of sleep duration that a particular individual needs to perform and live a healthy life. After all, like food and water, sleep is a need.”
Many factors can affect how much sleep you need, including:
- Activity levels
- Age
- Alcohol and caffeine consumption
- Diet
- Environment
- Emotional needs
- Genetics
- Health status
- Hormonal changes
- Lifestyle
- Medications
- Pregnancy
- Stress levels
“Shift work, inconsistent sleep schedules and exposure to blue light from electronic devices can also impact sleep patterns and requirements,” Siddiqui says.
Do some people need less sleep?
There is a small subset of people who can function normally with less sleep than the average person.
“Natural short sleepers are individuals who consistently sleep less than average yet feel fully rested and functional. Such people might regularly get only four to six hours of sleep per night,” says Dr. Ryan S. Sultan, research and medical director at Integrative Psych in New York City. “For example, variants of the DEC2 and ADRB1 genes would alter sleep regulation. These mutations enable more efficient sleep such that the person’s body needs less sleep than others.”
A 2020 cross-sectional study found a link between primary insomnia and polymorphisms in the NPSR1 gene. Mutations of the NPSR1, mGluR1 and β1-AR genes have also been shown to shorten sleep duration or need, according to a 2021 systemic review.
Do some people need more sleep?
Some people need more sleep during different life stages or with certain health conditions. “Individuals considered to be competitive athletes or those recovering from illness or stress may need more sleep for physical and mental recovery,” says Dr. Danielle Wall, sleep adviser for Sit ‘n Sleep in California.
Some studies suggest that most women also need around 13 minutes more sleep than men. The number may increase during certain times in their menstrual cycle and during menopause and pregnancy. “Typically, in the second half of their cycle, when estrogen declines and progesterone increases, women tend to require more sleep,” says Chelsie Rohrscheib, head sleep expert and neuroscientist at Wesper.
“Pregnant women, especially in the first trimester, often need more sleep due to hormonal changes,” Siddiqui says. Getting enough sleep during your last trimester can also help with labor and delivery. A 2015 study found that women who don’t get at least 6 hours of sleep may face longer labor and be at a higher risk of needing a Cesarean section.
A person’s sleep needs are highly individual, Holliday-Bell says. If you feel refreshed and ready for the day after nine hours instead of seven or eight, then your body or brain may need that extra time to recover, especially if you wake up during the night or don’t sleep well.
How does sleep affect health?
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Poor sleep quality -- whether from too little or too much sleep -- can significantly impact both mental and physical health.
“Army research has consistently shown that it only takes three days of getting less than 70% of daily sleep needs for any individual to be significantly physiologically and psychologically compromised by lack of sleep,” says Capt. Chris Enke, sleep readiness director for the US Army Holistic Health and Fitness program.
Sleep deprivation can lead to a wide range of issues. Wall notes it can cause:
- Memory loss
- Difficulty concentrating
- A weakened immune system
- Increased risk of high blood pressure, insulin resistance and heart disease
A 2010 systematic review and meta-analysis also found that sleeping 5 hours or fewer each night increases your risk of all-cause mortality. However, don’t let this cause too much anxiety. Everyone has poor sleep on occasion. It’s important to remember that one bad night -- or even a few -- won’t cause lasting harm.
Beyond physical health, sleep loss can take a toll on your emotional well-being. “When we’re sleep-deprived, people are more likely to feel irritable, anxious or down,” Sultan says. “In some cases, especially when sleep loss is severe, people can even experience intense symptoms like paranoia or hallucinations.”
Adolescents and young adults are particularly vulnerable. According to a 2014 report from the American Academy of Pediatrics, not getting enough sleep in these age groups is linked to higher rates of depression, mood disorders and suicidal ideation.
How to track sleep quality
CNET editor, Caroline Igo, tested 7 sleep trackers.
Monitoring your sleep quality can reveal whether you’re getting enough restful sleep, helping you determine if lifestyle changes are necessary for improvement. Carleara Weiss, sleep science adviser at Aeroflow Sleep, says a sign of good sleep quality is feeling “refreshed, energized, in a good mood and ready for your day.”
You can use a sleep diary to self-report sleep times and quality or a wearable sleep tracker, such as smart rings, smartwatches, sleep mats or mattress covers, to monitor heart rate, sleep stages and movement.
“The goal with any of these tools isn’t to chase a ‘perfect score,’ but to understand your habits. For instance, how long it really takes you to fall asleep or if you’re waking up more than you thought,” Sultan says. “That awareness can help you make better decisions around bedtime routines, screen use or caffeine.”
Wearables can offer helpful trends over time, but remember they aren’t always accurate when pinpointing sleep stages. Sultan recommends checking with your doctor or a sleep specialist if you wake frequently at night or feel exhausted during the day but have otherwise healthy habits.
Bottom line
Waking up early to workout can be a good thing, as long as you're getting 7-8 hours of sleep.
While general sleep guidelines suggest seven to nine hours for most adults, sleep isn’t one size fits all. Individual needs can vary based on age, genetics, lifestyle and overall health -- and it’s not just about how long you sleep, but how well.
Deep and REM sleep play essential roles in physical restoration, emotional regulation and cognitive function. Tracking your sleep quality and habits can help you better understand your unique needs and spot patterns so you can make informed changes to support better health and well-being.