Sleep Needs by Age
Updated March 28, 2019
The Importance of Sleep
When you think of what makes up a healthy lifestyle, diet and exercise come to mind, but did getting enough restful sleep? Some researchers consider the lack of sleep that many people get to be at epidemic levels.
According to the National Institutes of Health, lack of restful sleep causes a long list of issues:
- higher rates of obesity, high blood pressure, heart disease, stroke, Alzheimer's disease, certain cancers, and diabetes
- higher rates of depression and anxiety
- poor mood, energy, and motivation
- decreased focus, memory, and decision-making abilities
- decreased coordination, athletic performance, and higher rates of accidents
- lower levels of self-control, irritability, and more relationship problems
- inability to manage stress-small problems feel like much larger problems
- lowered immune function, frequent colds
- decreased sex drive
How Much Sleep Do We Need?
The National Sleep Foundation published a study by 18 sleep scientists and researchers in Sleep Health that shows the number of hours needed by all ages, divided into 9 age divisions. They're listed as ranges because gender has an influence, as well as lifestyle and health.
Newborns and Infants
Newborns don't have an established circadian rhythm; it isn't established they're 2-3 months old. Infants tend to sleep in several phases throughout the day (polyphasic), sleeping from 2.5 to 4 hours at a time. By around 12 months, infants start sleeping more at night. At this point, they start to sleep more like adults in that there are no bodily movements during REM (rapid eye movement) sleep, which is when people dream. Previous to 12 months, babies will move during REM sleep.
Recognizing when school-age children aren't sleeping enough can be difficult as tired kids tend to not slow down, they speed up. They'll engage in behaviors that look like ADHD. This includes resisting going to bed at night, even though they're tired.
Children with ADHD can cause sleep loss in children, as well as other issues such as sleep apnea (when people stop breathing for periods throughout the night). It was previously believed that sleep apnea only occurred in adults, but now the America Academy of Pediatrics recommends ask about and screen for sleep apnea in children.
According to the National Sleep Foundation, circadian rhythms shift after puberty, making teens want to go to bed after 11 pm and wake up later. With teenagers having the earliest start times, they are often getting up at 5 am to be at school by 7 am, which makes it rarer that a teen will get enough sleep. One study found that only 15% of teens reported sleeping 8.5 hours per night.
Because teens are sleep-deprived during the week, they sleep more on the weekend, which can make the problem worse. One of the top recommendations from sleep experts is to fall asleep and wake up at the same time every day.
A problem that many teens share with adults is the use of back-lit devices late at night, which can prevent sleepers from getting quality sleep.
Lack of sleep in teenagers has a long list of drawbacks, including:
- drowsy driving leading to car accidents
- reduced emotional control, leading to more fighting with parents, siblings, and peers
- poor cognitive ability, focus, decision making, and reaction time, leading to poor grades, athletic performance, and choices
- poor impulse control, which can create and strengthen bad habits
- skin issues such as acne
Adults tend to not get enough sleep for a list of reasons:
- stress from job and family
- consuming caffeine too late in the day
- looking at blue-light emitting devices within 90 minutes of going to bed
- inconsistent sleep schedule
- eating too late
- lack of exercise
- issues with the mattress: too hot, too soft or hard, and/or old
Many adults aged 65 and older nap during the day because they don't get enough quality sleep at night. One of the reasons they don't sleep well is because of medical conditions such as restless legs syndrome (RLS). The National Institutes of Health estimate that 10-35% of seniors have RLS, which results in uncomfortable sensations in the legs creating an irresistible urge to move them. Symptoms occur in the evening and often during sleep. Around 80% of people with RLS also have periodic limb movement disorder (PLMD), and one study found that around 45% of all seniors have at least mild PLMD.
Many seniors also suffer from illnesses and take medications, both of which can disturb sleep.
Another common issue among seniors is that it takes them longer to go to sleep, with one study showing 13% of men over 65 and 36% of women taking more than 30 minutes to fall asleep.
According to the National Sleep Foundation, seniors have trouble sleeping for several reasons. One is the change in the phases of sleep, where many seniors spend more time in the lighter phases of sleep and less in the deeper, more restorative phases.
Sleep fragmentation (waking up during the night) is also common, which greatly reduces the ability to wake up well rested.
Women need on average 20 more minutes per night more than men, though some women need more than that. One theory as to why is because women multitask more than men and have busier schedules, which results in their brains using more energy and therefore needing more recuperation. If this theory is correct, then men that have complex jobs that require a lot of decision-making and lateral thinking will need more than the average male as well. Another possible reason is the monthly hormone cycle that occurs with menstruation.
According to the National Institutes of Health, women do sleep more than men. However, there are several things that can make it difficult for women to get enough quality sleep:
- Their male partners' snore (40% of men snore as opposed to 24% of women)
- Stress from family and job responsibilities
Sleep Needs During Pregnancy
Pregnant women need more sleep, especially in their first trimester, which includes more sleepiness during the day. This is due to the rise in progesterone, as well as the metabolic changes the body is going through.
They also are more likely to experience parasomnias, which are unusual behaviors that occur just before falling asleep, during sleep, or when waking up. Common parasomnias for expecting mothers are restless legs syndrome (RLS), snoring, and insomnia.
Expectant mothers in their first trimester will also have more frequent bathroom visits to urinate, due to the uterus pushing on the bladder. Swollen breasts, cramps, and nausea can also make it hard to fall asleep.
In the second trimester, women tend to sleep better, as many of the changes have already occurred in the first trimester. However, it's not uncommon to experience leg cramps (often in the calves) as well as heartburn (due to the uterus pushing on the stomach).
In the third trimester, sleep gets worse again due to (RLS), frequent urination, anxiety about the upcoming delivery, and lower back pain.
After the baby is born, new mothers will often find it easier to sleep because they're sleep deprived. Babies are often awake every hour to few hours, so mothers can't get into the deeper, restful phases of sleep, so when they get a chance to sleep, the brain will try to make up the sleep deficit as quickly as possible.
Breastfeeding is sleep-inducing because the hormone that promotes lactation, prolactin, is a soporific, or sleep-promoting.
Can You Make Up Your Sleep Debt?
Some people believe that they can not sleep enough for several day or more and make it up when they get around to it. For many people, on a short-term basis, that looks to be true. If you are sleep deprived during the week, you may be able to make it up during the weekend.
But with long-term sleep debt, the evidence isn't good for being able to make it up. According to the Clayton Sleep Institute, research showed that six nights of sleep deprivation resulted in negative impacts on attention, daytime sleepiness, and inflammation. After a catch-up period to make up the sleep debt, attention levels didn't catch up. Cortisol, the prime marker for inflammation, didn't decrease either. A separate study showed that chronic sleep loss results in a loss of neurons that are responsible for alertness and cognition.
Another issue with sleep debt is that when you sleep too little, then sleep a lot, your circadian rhythm is disturbed. Many sleep experts believe that the number one thing you can do to start sleeping better is to fall asleep and wake up at the same time every day, regardless of whether it's a weekday or weekend. Have a regular sleep routine that gets you well rested, and there will be no need for a feast or famine sleep routine.
If you have a long-term sleep debt, experts recommend adding an extra hour or two of sleep per night, with no alarm clock, until you gradually start sleeping less.
It's also a good idea to make sure that you're getting the highest quality rest by following a good sleep protocol, which includes:
The Truth About Naps
A 15 to 20-minute nap can be a great way to help get rid of a sleep deficit. If you sleep longer than 20 minutes, you risk going into a deeper sleep, and when you wake up you could be groggy for a while. The length of a full sleep cycle is around 90 minutes, so if you sleep for 90 minutes, you may not wake up groggy, though it may be more difficult for you to fall asleep at night.
Early risers tend to want to nap around 1 pm, and late risers an hour or two later. As long as you nap early in the afternoon, and not in the evening, it shouldn't affect your ability to sleep at night.
Sleep Deprivation in Babies and Children
The younger a person is, the more sleep they require to help facilitate the development of a growing body and brain. According to the National Sleep Foundation, when a child hasn't slept enough, they may not always slow down, but they may speed up. Their behavior may look more like symptoms of ADHD, and they'll resist going to bed.
A few things that can help get a child to bed include:
- a bedtime between 7 pm and 8 pm
- a consistent sleep routine, such as brushing their teeth, reading a story, followed by lights out at the same time every night
- no sugar and caffeine in the evening
Signs of Sleep Deprivation in Adults
Do you know anyone that brags about not needing more than 4 or 5 hours per sleep per night? Have you wondered how much more work you could get done if you didn't need to sleep 7-9 hours per night? Do you belong to company that looks at not sleeping as a badge of honor?
It turns out that lack of sleep can make you a lot less productive, and only rare people can be well-rested on 4-5 hours per night of sleep.
You may be sleep deprived if you find yourself doing any of these things:
- want to sleep after eating
- fall asleep while reading or while watching t.v.
- you hit the snooze button multiple times in the morning
- every once in a while you "crash" and sleep for many hours on end
- rely on caffeine and sugar to keep your energy levels up
You can be sleep deprived even though you may sleep the recommended 7-9 hours per night because you're not getting quality sleep. If you have any of the following problems, you're probably not getting enough restful sleep:
- it takes you a long time to fall asleep once you go to bed
- you wake up multiple times throughout the night
- you wake up feeling tired
Sleep Deprivation and Weight Gain
Many people attribute their inability to lose weight to a lack of disciple. They feel guilty because they can't stick to a diet and exercise schedule, which can lead to emotional eating.
The reality for many people struggling to lose weight is that the lack of restful sleep impacts their brain's hormone production. When you don't get enough sleep, your leptin levels go down, and as leptin is the hormone that helps you feel satisfied and stop eating, you feel the need to continue eating.
Your ghrelin levels also go up, which is the hormone that stimulates your appetite.
In addition to ghrelin and leptin levels, researchers at the University of California Berkeley have found that when people are tired, they're more likely to eat foods that are bad for them. This can become a vicious cycle where you don't sleep well, so you eat more food, and worse food, which may make you sleep worse.
How to Get More Restful Sleep
If you suspect that you have a sleep disorder, it's best to talk to your doctor. But most people can look at a thorough sleep hygiene program and find at least a few things that they could improve on. Some of the most common mistakes that people make that reduce the amount of restful sleep are:
- Exposing their brain to blue light from their cell phone, tablet, or tv within a few hours of going to bed. Blue light tells your brain that it's time to be active and blocks the production of melatonin, the "sleep hormone."
- Consuming caffeine and sugar before bed.
- Eating too much before bed.
- Reading work emails in bed and working until bedtime.
- Having a stressful lifestyle.
- Going to bed and waking up at different times every day, which disturbs your circadian rhythm.
- Sleeping on a mattress that's too hard, too soft, or old. If you wake up with back or joint pain, you may be on the wrong mattress.
- Sleeping on a mattress that gets too hot.
- Having anxiety that you won't sleep good, which can prevent you from sleeping well.
- Lack of exercise, which is a great way to relieve stress and has been linked to better sleep.