- Most healthy adults need between seven and nine hours of sleep each night.
- Infants, young children, and teenagers should get more sleep to support their growth and development.
- Feel like you’re constantly chasing sleep but never sure if you’re getting enough? Figuring out how much sleep you actually need can feel like solving a mystery. But sleep isn’t a luxury—it’s a biological necessity—and getting the right amount can mean the difference between powering through your day and dragging yourself through it.
How Many Hours of Sleep Do You Need?
As a basic rule, healthy adults need at least seven hours of sleep per night . Babies, young children, and teens need even more sleep to enable their growth and development .
Getting less than seven hours has been linked to a weakened immune system, reduced job performance, and a heightened risk of accidents (including car accidents). An ongoing lack of sleep is also associated with many serious health issues, including high blood pressure, heart disease, weight gain, obesity, diabetes, and depression.
If seven hours is the minimum, a natural follow-up question is whether adults can sleep too much. According to experts, the answer isn’t so clear. Sometimes sleeping more than nine hours is a sign of an underlying health problem, but getting extra sleep can be appropriate in certain circumstances, such as when you’re sick or trying to catch up on sleep.
Recommended Hours of Sleep by Age
The amount of sleep a person needs depends on their age. Experts at organizations like the American Academy of Sleep Medicine, Sleep Research Society, and the American Academy of Pediatrics have endorsed a recommended sleep chart by age.
There’s no specific recommendation for newborns, because there’s limited research about how much sleep they truly need. That said, babies under four months often sleep between 14 and 17 hours per day
Finding the Right Amount of Sleep for You
These guidelines serve as a rule of thumb for how much sleep babies, children, and adults need. Experts acknowledge that the ideal amount of sleep can vary from person to person . Some people need more or less sleep than the suggested amount for their age.
Deciding how much sleep you need means considering your overall health, daily activities, and typical sleeping patterns. Some questions that can help you assess your individual sleep needs include:
- Are you productive, healthy, and happy on seven hours of sleep? Or have you noticed that you require more hours of sleep to get into high gear?
- Do you unwillingly doze off during the day?
- Do you have health issues that might require more rest? Are you taking any medications that affect your sleep or daytime energy levels?
- Do you have a high level of daily energy expenditure? Do you frequently play sports or work in a labor-intensive job?
- Do your daily activities require alertness to do them safely? Do you drive every day or operate heavy machinery? Do you feel sleepy while doing these activities?
- Are you experiencing or do you have a history of a sleep disorder?
- Do you depend on caffeine to get you through the day?
- When you have an open schedule, do you tend to sleep more?
- Are you pregnant or breastfeeding?
You can use your answers to these questions to hone in on your optimal amount of sleep. You can also talk to your doctor to review your overall health, your typical sleep patterns, and whether you might need more or less sleep than recommended.
You may find that having sleep-related data can help you think about these questions. For example, keeping a sleep diary or wearing a sleep tracker may help you detect trends in how you sleep at night and how it affects you during the day.
Sleep Quality vs. Quantity
When thinking about sleep needs, it’s easy to focus on quantity. But a good night’s rest isn’t just about how many hours you’re asleep—the quality of your sleep is just as important.
Low-quality sleep often feels restless or disrupted, making it less refreshing than solid, continuous sleep . Fragmented sleep hinders your ability to progress through the four stages of sleep, all of which are necessary for healthy sleep .
Research is increasingly finding that poor quality sleep can be just as harmful as a reduced quantity of sleep . Disrupted sleep has been linked to many symptoms of sleep deprivation, including impaired memory and poor mood . Low-quality sleep may also raise long-term risks of numerous mental and physical health problems .
REM and Deep Sleep
Each night, we move through multiple sleep cycles that last 90 to 120 minutes . These sleep cycles are made up of four stages of sleep. All four stages are important to good sleep, but two specific stages have an especially big impact.
During deep sleep, also known as stage 3 sleep, your breathing and heart rate slow down, and your brain and body relax . This aids in your body’s rest and recovery, allowing you to wake up feeling rejuvenated.
Deep sleep also contributes to the health of your immune system, bones, and other tissues . On most nights, deep sleep makes up around 10% to 20% of your total sleep time, or about 90 minutes if you sleep for seven to eight hours .
Rapid eye movement (REM) sleep is the last sleep stage, and it usually makes up 20% to 25% of your time asleep (or about two hours) . During REM sleep, your pulse and breathing get faster, and brain activity picks up significantly, almost to the level of being awake . Dreaming is most active and intense during REM sleep. Research has found REM sleep is important for memory, mood, and overall brain function.
How Do You Know if You’re Getting Enough Sleep?
It’s challenging to know if you’re actually getting enough sleep. Reflecting on three key factors can help determine if you’re getting the right amount of rest.
- How you wake up: If you feel refreshed when you wake up, that’s a good sign. If you struggle to start your day, it may indicate that you’re short on sleep.
- Sleepiness during the day: If you find that you’re nodding off or extremely tired during the day, it could be a result of insufficient sleep at night.
- Your concentration levels: Good sleep helps you focus, so if you have trouble with concentration, it might be because you’re not getting enough sleep.
What Happens if You Don’t Get Enough Sleep?
Not getting enough sleep can have far-reaching consequences. Some of the immediate signs of sleep deprivation include:
- Extreme tiredness during the day
- Slowed thinking and reaction time, heightening the risk of errors and accidents
- Reduced focus and memory
- Irritability
- Feelings of anxiety or depression
If insufficient sleep becomes a lasting problem, it can also give rise to other health issues, including:
- High blood pressure, heart problems, and stroke
- Decreased immune function
- Type 2 diabetes
- Kidney disease
- Obesity