How Much Sleep Do You Need?
Signs that You’re Not Getting Enough and What to Do About It
When you’re scrambling to meet the demands of a busy schedule, cutting back on sleep may seem like the only answer. Sacrificing an hour or two of rest in order to get more done may sound like a reasonable trade-off. But the truth is that even minimal sleep loss takes a toll on your mood, energy, mental sharpness, and ability to handle stress. And over the long-term, chronic sleep loss wreaks havoc on your health.
By understanding your nightly sleep needs and what you can do to bounce back from chronic sleep loss, you can finally get on a healthy sleep schedule.
Sleep is a necessity, not a luxury
The quality of your sleep directly affects the quality of your waking life, including your productivity, emotional balance, creativity, physical vitality, and even your weight. No other activity delivers so many benefits with so little effort!
Sleep isn’t merely a time when your body shuts off. While you rest, your brain stays busy, overseeing a wide variety of biological maintenance that keeps your body running in top condition, preparing you for the day ahead. Without enough hours of restorative sleep, you won’t be able to work, learn, create, and communicate at a level even close to your true potential. Regularly skimp on “service” and you’re headed for a major mental and physical breakdown.
The good news is that you don't have to choose between health and productivity. As you start getting the sleep you need, your energy and efficiency will go up. In fact, you're likely to find that you actually get more done during the day than when you were skimping on shuteye.
Myths and Facts about Sleep
Myth 1: Getting just one hour less sleep per night won’t affect your daytime functioning. You may not be noticeably sleepy during the day, but losing even one hour of sleep can affect your ability to think properly and respond quickly. It also compromises your cardiovascular health, energy balance, and ability to fight infections.
Myth 2: Your body adjusts quickly to different sleep schedules. Most people can reset their biological clock, but only by appropriately timed cues—and even then, by one or two hours per day at best. Consequently, it can take more than a week to adjust after traveling across several time zones or switching to the night shift.
Myth 3: Extra sleep at night can cure you of problems with excessive daytime fatigue. The quantity of sleep you get is important, sure, but it's the quality of your sleep that you really have to pay attention to. Some people sleep eight or nine hours a night but don’t feel well rested when they wake up because the quality of their sleep is poor.
Myth 4: You can make up for lost sleep during the week by sleeping more on the weekends. Although this sleeping pattern will help relieve part of a sleep debt, it will not completely make up for the lack of sleep. Furthermore, sleeping later on the weekends can affect your sleep-wake cycle so that it is much harder to go to sleep at the right time on Sunday nights and get up early on Monday mornings.
Adapted from: Your Guide to Healthy Sleep, The National Institutes of Health
How many hours of sleep do you need?
According to the National Institutes of Health, the average adult sleeps less than seven hours per night. In today’s fast-paced society, six or seven hours of sleep may sound pretty good. In reality, though, it’s a recipe for chronic sleep deprivation.
|Average Sleep Needs by Age|
Newborn to 2 months old
12 - 18 hrs
3 months to 1 year old
14 - 15 hrs
1 to 3 years old
12 - 14 hrs
3 to 5 years old
11 - 13 hrs
5 to 12 years old
10 - 11 hrs
12 to 18 years old
8.5 - 10 hrs
7.5 - 9 hrs
There is a big difference between the amount of sleep you can get by on and the amount you need to function optimally. Just because you're able to operate on seven hours of sleep doesn't mean you wouldn't feel a lot better and get more done if you spent an extra hour or two in bed.
While sleep requirements vary slightly from person to person, most healthy adults need between 7.5 to 9 hours of sleep per night to function at their best. Children and teens need even more (see Average Sleep Needs table above). And despite the notion that our sleep needs decrease with age, older people still need at least 7.5 to 8 hours of sleep. Since older adults often have trouble sleeping this long at night, daytime naps can help fill in the gap.
The best way to figure out if you're meeting your sleep needs is to evaluate how you feel as you go about your day. If you're logging enough hours, you'll feel energetic and alert all day long, from the moment you wake up until your regular bedtime.
Think six hours of sleep is enough?
Think again. Researchers at the University of California, San Francisco, discovered that some people have a gene that enables them to do well on six hours of sleep a night. This gene, however, is very rare, appearing in less than 3% of the population. For the other 97% of us, six hours doesn’t come close to cutting it.
Signs that you’re not getting enough sleep
If you’re getting less than eight hours of sleep each night, chances are you’re sleep deprived. What’s more, you probably have no idea just how much lack of sleep is affecting you.
How is it possible to be sleep deprived without knowing it? Most of the signs of sleep deprivation are much more subtle than falling face first into your dinner plate. Furthermore, if you’ve made a habit of skimping on sleep, you may not even remember what it feels like to be wide-awake, fully alert, and firing on all cylinders. Maybe it feels normal to get sleepy when you’re in a boring meeting, struggling through the afternoon slump, or dozing off after dinner, but the truth is that it’s only “normal” if you’re sleep deprived.
You may be sleep deprived if you...
- Need an alarm clock in order to wake up on time
- Rely on the snooze button
- Have a hard time getting out of bed in the morning
- Feel sluggish in the afternoon
- Get sleepy in meetings, lectures, or warm rooms
- Get drowsy after heavy meals or when driving
- Need to nap to get through the day
- Fall asleep while watching TV or relaxing in the evening
- Feel the need to sleep in on weekends
- Fall asleep within five minutes of going to bed
The effects of chronic lack of sleep
While it may seem like losing sleep isn't such a big deal, sleep deprivation has a wide range of negative effects that go way beyond daytime drowsiness. Lack of sleep affects your judgment, coordination, and reaction times. In fact, sleep deprivation can affect you just as much as being drunk.
The effects include:
- Fatigue, lethargy, and lack of motivation
- Moodiness and irritability
- Reduced creativity and problem-solving skills
- Inability to cope with stress
- Reduced immunity; frequent colds and infections
- Concentration and memory problems
- Weight gain
- Impaired motor skills and increased risk of accidents
- Difficulty making decisions
- Increased risk of diabetes, heart disease, and other health problems
How sleep deprivation can add to your waistline
Ever noticed how when you’re short on sleep you crave sugary foods that give you a quick energy boost? There’s a good reason for that. Sleep deprivation has a direct link to overeating and weight gain.
There are two hormones in your body that regulate normal feelings of hunger and fullness. Ghrelin stimulates appetite, while leptin sends signals to the brain when you are full. However, when you don’t get the sleep you need, your ghrelin levels go up, stimulating your appetite so you want more food than normal, and your leptin levels go down, meaning you don’t feel satisfied and want to keep eating. So, the more sleep you lose, the more food your body will crave.
Paying off your sleep debt
Sleep debt is the difference between the amount of sleep you need and the hours you actually get. Every time you sacrifice on sleep, you add to the debt. Eventually, the debt will have to be repaid; it won’t go away on its own. If you lose an hour of sleep, you must make up that extra hour somewhere down the line in order to bring your “account” back into balance.
Sleeping in on the weekends isn’t enough!
Many of us try to repay our sleep debt by sleeping in on the weekends, but as it turns out, bouncing back from chronic lack of sleep isn’t that easy. One or two solid nights of sleep aren’t enough to pay off a long-term debt. While extra sleep can give you a temporary boost (for example, you may feel great on Monday morning after a relaxing weekend), your performance and energy will drop back down as the day wears on.
Tips for getting and staying out of sleep debt
While you can’t pay off sleep debt in a night or even a weekend, with a little effort and planning, you can get back on track.
- Aim for at least seven and a half hours of sleep every night. Make sure you don’t fall farther in debt by blocking off enough time for sleep each night. Consistency is the key.
- Settle short-term sleep debt with an extra hour or two per night. If you lost 10 hours of sleep, pay the debt back in nightly one or two-hour installments.
- Keep a sleep diary. Record when you go to bed, when you get up, your total hours of sleep, and how you feel during the day. As you keep track of your sleep, you’ll discover your natural patterns and get to know your sleep needs.
- Take a sleep vacation to pay off a long-term sleep debt. Pick a two-week period when you have a flexible schedule. Go to bed at the same time every night and allow yourself to sleep until you wake up naturally. No alarm clocks! If you continue to keep the same bedtime and wake up naturally, you’ll eventually dig your way out of debt and arrive at the sleep schedule that’s ideal for you.
- Make sleep a priority. Just as you schedule time for work and other commitments, you should schedule enough time for sleep. Instead of cutting back on sleep in order to tackle the rest of your daily tasks, put sleep at the top of your to-do list.
Improving sleep quality
It's not just the number of hours in bed that's important—it's the quality of those hours of sleep. If you're giving yourself plenty of time for sleep, but you're still having trouble waking up in the morning or staying alert all day, you may not be getting quality sleep.
The most damaging effects of sleep deprivation are from inadequate deep sleep. Deep sleep is a time when the body repairs itself and builds up energy for the day ahead. It plays a major role in maintaining your health, stimulating growth and development, repairing muscles and tissues, and boosting your immune system. In order to wake up energized and refreshed, getting quality deep sleep is essential.
Factors that can lead to poor or inadequate deep sleep include:
- Being woken during the night by outside noise, for example, or in order to care for a crying baby.
- Working night shifts or swing shifts. Getting quality deep sleep during the day can be difficult, due to light and excess noise.
- Smoking or drinking in the evening. Substances like alcohol and nicotine can disrupt deep sleep. It’s best to limit them before bed.
- Exposure to artificial light at night—especially the light from electronic devices, including TVs, computers, tables, and mobile phones.
Sleep habits that make a difference
You have more control over the quality of your sleep than you might think. The following simple sleep tips can make a huge difference.
- Stick to a regular sleep-wake schedule, even on weekends.
- Avoid screens (TV, phone, tablet, computer) within 2 hours of your bedtime.
- Make sure your bedroom is dark, cool, and quiet. Curtains, white noise machines, and fans can help.
Sleep tips for night and swing shift workers
A disrupted sleep schedule caused by working nights or irregular shifts can lead to sleepiness in the work place, affect your mood, energy, and concentration, and increase your risk of accidents, injuries, and work-related mistakes. Shift workers tend to suffer from two problems: sleeping at home during the day and staying awake at work during the night. To avoid or limit these problems:
- Limit the number of night or irregular shifts you work in a row to prevent sleep deprivation from mounting up. If that’s not possible, avoid rotating shifts frequently so you can maintain the same sleep schedule.
- Avoid a long commute that reduces sleep time. Also, the more time you spend traveling home in daylight, the more awake you’ll become and the harder you’ll find it to get to sleep.
- Drink caffeinated drinks early in your shift, but avoid them close to bedtime.
- Take frequent breaks and use them to move around as much as possible—take a walk, stretch, or even exercise if possible.
- Adjust your sleep-wake schedule and your body’s natural production of melatonin. Expose yourself to bright light when you wake up at night, use bright lamps or daylight-simulation bulbs in your workplace, and then wear dark glasses on your journey home to block out sunlight and encourage sleepiness.
- Eliminate noise and light from your bedroom during the day. Use blackout curtains or a sleep mask, turn off the phone, and use ear plugs or a soothing sound machine to block out daytime noise.
- Make sleep a priority at the weekends or on your nonworking days so you can pay off any sleep debt.
If stress, worry or relationship issues are making it harder for you to sleep, read FEELING LOVED.
More help for sleep
- How to Sleep Better: Tips for Getting a Good Night’s Sleep
- How to Sleep Well As You Age: Tips for Overcoming Insomnia and Sleeping Better Over 50
- Sleeping Pills and Natural Sleep Aids: What's Best for You?: What You Need to Know About Sleep Aids and Sleeping Pills
Resources and references
Brain Basics: Understanding Sleep – Learn about sleep benefits and sleep needs, dreaming, circadian rhythms, sleep cycles and stages, and sleep disorders. (National Institute of Neurological Disorders and Stroke)
Your Guide to Healthy Sleep (PDF) – Comprehensive guide to sleep and why it matters. Learn about the stages and cycles of sleep, the dangers of sleep deprivation, and dealing with common sleep problems. (National Institutes of Health)
Assess Your Sleep Needs – Learn about typical sleep needs and how to determine your own nightly needs. (Get Sleep, Harvard Medical School Division of Sleep Medicine)
How Much Sleep Do We Really Need? – Research on sleep needs and sample sleep requirements in different age ranges. (The National Sleep Foundation)
How Much Sleep Is Enough for My Child? – Figure out if your child is getting adequate sleep and learn about the sleep needs of different age groups. (KidsHealth)
Sleep deprivation and sleep debt
Effects of Sleep Deprivation – Learn about the consequences of sleep deprivation and how you can pay off your sleep debt. (Stanford Sleep & Dreams)
Consequences of Insufficient Sleep – Series of articles and videos on the consequences of sleep deprivation and chronic lack of sleep, including its impact on driving, judgment, and disease risk. (Harvard Healthy Sleep Web Site)
Can You Catch Up on Lost Sleep? – Explore the consequences of sleep debt, including its effects on health, productivity, and performance. Includes tips on how to repay sleep debt. (Scientific American)