One of the biggest sleep myths out there is that everyone, regardless of age, needs eight hours of sleep per night. While this may be true for some, it’s far too simplistic to apply a one-size-fits-all statement like this to something as complex and individual as sleep. Below, we’re busting the myths and outlining the facts to help you better understand what amount of sleep is right for you.
The two functions affecting sleep
- Circadian rhythm
The body has several internal biological clocks running behind-the-scenes to maintain processes and functions. The 24-hour circadian rhythm—derived from the Latin circa (around) and diem (a day)—regulates the sleep-wake cycle, or internal clock.
- Homeostatic drive
Homeostatic drive functions more as an internal timer, meaning the longer someone is awake, the higher the pressure is to get to sleep.
Sleep need by age
0 - 3 months: 14 - 17 hours
In terms of quantity, newborns need the most amount of sleep (14 - 17 hours) in order to support memory and the processing of sensory stimuli. (1)
4 - 11 months: 12 - 15 hours
Come toddler age, the quantity of sleep decreases slightly but is still on the longer end.
3 - 5 years: 10 - 13 hours
Between the ages of three and five, which is generally preschool age, kids need between 10 and 13 hours of sleep.
6 - 13 years: 9 - 11 hours
The next age group covers mid-childhood, during the pre-teen years when school-aged children need between nine and 11 hours of sleep per night.
14 - 18 years: 8 - 10 hours
Come adolescence, the amount of sleep decreases slightly (from 9-11 to 8-10).
25 - 45 years: 7 - 9 hours
46 - 65 years: 7 - 9 hours
70 - 90 years: 7 - 9 hours
The final three groups all hover in the range of 7-9 hours per night, which is where the average of eight comes in for both young adults and older adults.
How the distribution of REM sleep changes with age
There are four key stages of sleep. The first three are considered non-rapid eye movement sleep (NREM sleep or non-REM sleep), which is known as quiet sleep. The fourth is rapid eye movement (REM sleep), which is more active.
Come adulthood, the amount of time spent in stage 3 (deep sleep, otherwise known as slow wave sleep) decreases while the proportion of sleep in stage 1 and 2 increases. The effect of age on REM sleep, however, is minimal, with researchers finding a 0.6% decrease per decade from age 19 to 75, followed by smaller increases from age 75 to 85. (2)
Genetics play a role in your sleep need
While everyone’s sleep need is variable, some of it may be hard-wired. Researchers at the University of California, San Francisco, identified a mutation in the β1-adrenergic receptor gene among those who require fewer hours of sleep than most within their age bracket. (3)
Frequently asked questions
How do I know if I’m suffering from sleep deprivation...or if I just don’t need that much sleep?
Unlike insomnia, which occurs when you have difficulty sleeping despite an adequate opportunity to do so, sleep deprivation refers to the lack of an opportunity to satisfy the physiological need to sleep. (4) External restrictions to sleep that cause deprivation can include everything from staying up all night to finish an assignment to working overnight as a nurse. Deprivation occurs when you get fewer than eight hours of sleep a night over an extended period of time, thus disrupting sleep patterns and stages.
I tend to experience poor sleep because of how much I snore! What should I do?
If this is the case, you may be suffering from Excessive Daytime Sleepiness due to sleep apnea, a sleep disorder marked by temporary pauses in breathing through the night. A major risk factor for apnea is obesity; however, it’s also particularly common among menopausal women—studies indicate that about 20% develop some form of the condition. (5) Apnea exists on a spectrum, meaning it doesn’t manifest the same way for everyone. Some experience mild, general snoring due to upper airway resistance that doesn’t affect blood oxygen levels while others have more severe cases in which blood oxygen levels drop. Known as hypoxemia, this stresses out the entire body and can contribute to hypertension, stroke risk, cardiovascular disease, etc.
In order to diagnose apnea, your healthcare provider or sleep medicine specialist may recommend you enroll in an overnight sleep study known as a polysomnography (or PSG), in which multiple EEG sensors are placed on the head to identify brainwaves and differentiate when you're awake or asleep (and in what stage). There are other sensors that also track breathing, snoring, limb movement, and heart rate across the night.
Will daytime naps affect nighttime sleep duration?
Napping during the day decreases the "hunger" for shut-eye come nighttime and may not be best if you have trouble falling asleep at night or suffer from insomnia. That being said, not everyone's situation is the same. Some people have to nap to help them through the remainder of the day, so if you must, consider if it's possible to decrease the duration to get enough sleep at night. Generally speaking, short naps don't affect nighttime sleep quality for most.
What are some healthy sleep tips to help me get closer to the general range for my age group?
We've compiled a comprehensive blog post with 16 science-backed things to try if you're not getting a good night's sleep. The tips for better sleep habits are split into the following categories:
- During your nighttime, pre-sleep routine
- If you can't fall asleep
- If you wake up in the middle of the night
- If you wake up too early
If you're trying to sleep better, it may be worth taking a look at your diet, too. These are the 15 best and worst foods for your sleep—and overall health and wellness—beyond the obvious coffee and chocolate.