Your brain also has a built-in "clock,” called your “circadian rhythm,” that tells you when it’s time to sleep or wake up. This clock likes darkness at night, which is why it's harder to sleep in bright rooms.
Why is sleep so important?
Sleep is essential for your health — it’s kind of like recharging your body’s battery! Getting the right amount of sleep helps you:
- Feel energized for sports and play
- Make healthier food choices
- Fight off sickness and get well sooner if you do get sick
- Focus better in school
- Stay at a healthy weight and lower the chance of getting diabetes
- Feel happier and handle emotions better
But studies show that about a third of 6- to 12-year-olds and more than half of teens do not get the sleep they need. Given the health benefits of sleep and the risks of not getting enough sleep, it’s important to take kids’ sleep seriously.
Rest to recharge: Sleep strategies for kids
Getting enough sleep is essential for growing brains and bodies, but it can be tough without the right habits and environment. You can learn how much sleep your body needs — and simple strategies for getting it — by following the links below. Each one includes tips for creating a calm, sleep-friendly space that makes it easier to wind down and rest well.
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What are the two types of sleep?
You cycle through two types of sleep every night: non-rapid eye movement (NREM) and rapid eye movement (REM). During the night, you cycle through both states several times:
- During quiet sleep (NREM), your body heals, grows, and recharges its energy.
- While in active sleep (REM), your brain is busy dreaming, your heart beats faster, your blood pressure increases, and you start breathing irregularly.
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When you're a child, this clock usually makes you feel tired earlier in the evening and wake up earlier in the morning (for example, around 8 p.m. and 6 a.m.). As you become a teen, this clock shifts a bit, causing you to naturally feel tired later at night and wake up later in the morning (for example, around 11 p.m. and 8 a.m.). That’s why some middle schools and high schools start later in the morning than elementary schools.
What happens when kids don’t get enough sleep?
A busy schedule can make getting enough sleep tough. School, homework, sports, hanging out with friends, and screen use can all use up some of your sleep time.
Without enough sleep, you might:
- Feel too tired for sports or play
- Eat more unhealthy food because you're extra hungry
- Have trouble concentrating or remembering things
- Need naps after school, making it even harder to sleep at night
- Feel cranky or upset more easily
- Feel more stressed
- Get sick more often
How does sleep impact hormones?
Inadequate sleep can affect many of the hormones that play a role in how your body manages hunger and food:
Leptin: A “satiety hormone”
Leptin is a “satiety hormone” released from fat cells. It decreases when you don’t get enough sleep, making you feel less full after eating.
Ghrelin: A “hunger hormone”
Ghrelin is a “hunger hormone” released from stomach cells. It increases when you don’t get enough sleep, making your body crave more calories.
Cortisol: A “stress hormone”
Cortisol is a “stress hormone” released from the adrenal glands. It increases when you don’t get enough sleep. If cortisol is too high for too long, it can increase belly fat and interfere with metabolism (such as the way your body converts calories from food into energy).
Insulin: A “calorie-storage hormone”
Insulin is a “calorie-storage hormone” released from the pancreas. It moves sugar out of the bloodstream into cells, where it is burned for energy or stored for later use. People who don’t get enough sleep are more likely to develop insulin resistance and are at higher risk of type 2 diabetes.
How does sleep impact nutrition, fitness, sedentary time, and stress?
Inadequate sleep also can affect the other health behaviors covered in the Boston Children’s fit kit:
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Sleep and nutrition
People who don’t get enough sleep tend to eat more high-glycemic foods (such as chips and sweets) and drink more soda and other sugary beverages. To complicate matters, some people eat high-glycemic foods as a bedtime snack. This is not a good strategy, because high-glycemic foods have been linked to overeating and weight gain.
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Sleep and fitness
Children who do not get enough sleep may feel tired throughout the day and less motivated to participate in physical activity and exercise, leading to decreased levels of fitness. Yet too little physical activity leads to poor quality sleep. This can cause an unhealthy cycle of not getting enough sleep and not having energy for physical activity, followed by more trouble falling asleep.
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Sleep, sedentary time, and stress
Children who are tired from not getting enough sleep often spend more time sitting around (sedentary time), sometimes on social media. This can increase risk of becoming emotionally wrapped up in social media, which may increase stress and make it harder to sleep. Together, poor sleep plus high stress can raise a child’s stress response and cortisol levels even higher.
Glossary
What do these sleep words mean?
- Circadian rhythms: Cycles such as the sleep-wake cycle that control body functions. Circadian rhythms are controlled by a “biological clock” in the brain, which is regulated by light and darkness.
- Hunger: Feelings of discomfort coupled with the desire to eat, often caused by low blood sugar.
- Insulin resistance: A condition that happens when cells in muscles, fat, and liver do not respond well to insulin, leading to elevated levels of blood sugar. Insulin resistance can lead to type 2 diabetes.
- Non-Rapid Eye Movement (NREM) sleep: “Quiet” sleep during which blood supply to the muscles is increased, energy is restored, tissue growth and repair occur, and hormones are released for growth and development.
- Rapid Eye Movement (REM) sleep: “Active” sleep during which dreams occur. The body is immobile, heart rate and blood pressure increase, and breathing is irregular.
- Satiety: State of feeling full after eating.
- Type 2 diabetes: A disease that develops when the pancreas cannot make enough insulin to overcome insulin resistance.
- White noise: Steady, unvarying, and unobtrusive background sounds that mask or block out other sounds and can make it easier to fall asleep.