4–6 hours7–9 hours10–12 hours13–17 hours
Adults need 7–9 hours of sleep each night!
Research shows that adults (ages 24 to 64) need this much sleep to maintain overall health. However, the exact amount an adult needs can vary depending on lifestyle factors like work schedule, illness, and stress, which affect the quality and quantity of sleep they get.
4–6 hours8–10 hours12–15 hours19–23 hours
Infants need 12–15 hours of sleep each night!
That's a lot of sleep! And there's no guarantee that infants will sleep for that long without crying breaks. Find out more about the sleep needs of babies and toddlers here.
Melatonin is the sleep hormone!
Melatonin decreases alertness and makes you feel sleepy. It's made in the brain's pineal gland, which gets "turned off" during the day when there's sunlight. It turns back on at night when it gets dark. You can also buy synthetic melatonin pills if you find out your body has trouble producing its own.
One-fifth (1/5)Via zak00 / ThinkstockOne-third (1/3)Via zak00 / ThinkstockOne-half (1/2)Via zak00 / Thinkstock
Humans spend up to one-third of their lives asleep!
Spending nearly 35% of your life asleep might sound like a lot of lost time, but you need sufficient sleep to survive — just like you need food and water.
False — alcohol does not help you sleep!
Alcohol may help you fall asleep faster because of its relaxing effect, but it harms both the quality and quantity of sleep you get. Booze disrupts stages of deep sleep (specifically REM), making your overall sleep less restful. That means you'll feel more tired the next day, and if you have insomnia or sleep apnea, it could make it worse.
Fruit saladVia bhofack2 / ThinkstockFries and ketchupVia Miroha141 / ThinkstockChocolate ice creamVia tacar / ThinkstockChips and salsaVia cobraphoto / ThinkstockFried ChickenVia bofhack2 / ThinkstockAll of these foods.Via ekremguduk / Thinkstock
All of the foods pictured could mess with your sleep!
Fruit has natural sugars that get converted into energy, which could make it harder to fall asleep. Chocolate ice cream has a ton of sugar plus caffeine from the cocoa beans, which can keep you up, too. Finally, greasy, acidic, or spicy foods can increase acid reflux, especially when you're digesting laying down. The reflux and indigestion makes it harder to fall asleep and stay asleep.
When you only breathe out of your nose during sleep.When you have seizures in your sleep.When you move around so much in your sleep that it results in falling or injury.When you stop breathing or take very shallow breaths during sleep.
Sleep apnea is when your breathing pauses or you take shallow breaths during sleep.
According to the National Institutes of Health (NIH), these pauses can last from a few seconds to several minutes, AND they can happen up to 30 times an hour! When the person tries to breathe normally again, they often choke or snort loudly, which can wake them (and their bed partner) — so it can be very disruptive to sleep.
HigherLowerNeither — it stays the same.
Your body temperature is lower during sleep!
Body temperature is a very important part of sleep regulation. Your core body temperature drops to help you fall asleep, and it reaches its lowest point in a 24-hour day during the deep sleep stage of sleep. So, sleeping in a cold room can actually help you snooze!
Impaired drivingIrritabilityPoor decision-makingAll of the above
Sleep loss can cause impaired driving, irritability, and poor decision-making!
Sleep is essential for proper mental and physical functioning. Studies show that driving while sleep-deprived is almost as bad as driving drunk. Sleep loss can also worsen your mood and put you at a higher risk of depression. Finally, it has a huge impact on cognitive tasks like concentration and problem-solving.
The pattern of vibrations throughout the brain during sleep.The chirping rhythms that crickets make at night.Changes in your heartbeat during different stages of sleep.Changes in the body over a 24-hour period, controlled by our internal biological clock.
Our circadian rhythms are mental and physical changes in the body controlled by our biological clocks!
Circadian rhythms tell us when to fall asleep and when to wake up over the course of a 24-hour day, helping you to maintain a sleep routine. They are controlled by our body's "internal clock" as well as external cues like daylight, meal times, and sounds. You can disrupt circadian rhythms by changing time zones — called "jet lag" — or by pulling all-nighters.
There are five stages of sleep.
They are: stage one (light sleep), stage two (sleep onset), stages three and four (deep sleep), and REM sleep. One full sleep cycle lasts about 90 to 110 minutes. Your body alternates between stages one through four (the non-REM sleep stages) and the REM sleep stage throughout the night. NREM sleep makes up 75% (about 65 minutes) of your sleep cycle and it's the most restorative.
Rapid eye movementResting endocrine motilityRapid external motionResting eye movement
"REM" stands for rapid eye movement.
You enter REM sleep about 90 minutes after you fall asleep, and go into it every 90 minutes, alternating with the non-REM cycles. REM sleep periods get longer later in the night. During REM, your eyes move back and forth rapidly while the body supplies energy to the brain, which helps mental activities the next day.
Stages three and four (deep sleep)Stage two (sleep onset)REM sleepNo single stage
Most dreaming occurs during REM sleep!
Dreaming is a complicated process. But scientists do know that during REM sleep, the brain is most active. Certain signals activate parts of the brain involved in processing and storing information, memories, and images — all of these make up our dreams. Overall, dreams are a strange and personal experience.
These are more common in women!
There is growing research from the NIH that shows insufficient sleep and insomnia are more prevalent among women. Theories suggest it could be due to a difference in hormones, the effects of pregnancy, or other lifestyle factors.
You can't make up for lost sleep on the weekends!
According to the NIH, the body's internal processes (like your biological clock, hormones, etc) make it impossible to get used to significantly less sleep than your body needs. If you lose sleep several nights in a row, you acquire a "sleep debt," which affects brain function, cardiovascular health, and energy levels. Sleeping late on the weekends won't repay the debt or its toll on the body — you'll need many nights, or even a whole week, of optimal sleep to catch up.
When you can feel physical sensations (like falling or getting stabbed) during a nightmare.When you go into deep sleep with your eyes still partially open.When your body stays in deep sleep for too long and you stay sleeping for twice as long as normal.When your brain wakes up before your muscles and body wake up.
Sleep paralysis is when your brain wakes up before your body and muscles wake up!
During REM sleep, your voluntary muscles go into a state of paralysis, which prevents you from acting out your dreams and injuring yourself. During sleep paralysis, the body remains "paralyzed" in REM sleep but the brain wakes up and the eyes start to open. So you become semi-conscious, but you can't move any muscle or speak — this can last from seconds to minutes. Heart rate and breathing stay normal, so sleep paralysis won't kill you, but it's still scary AF.