It can be tempting to trade sleep for a few precious hours of wakefulness, but it is important to consider the hidden costs. Sleep is precious, too. Numerous studies have found that insufficient sleep increases a person's risk of developing serious medical conditions, including obesity, diabetes, and cardiovascular disease. Lack of adequate sleep over time has been associated with a shortened lifespan. Insufficient sleep may increase your risk of developing high blood pressure and cardiovascular disease.

It may seem obvious that sleep is beneficial. Even without fully grasping what sleep does for us, we know that going without sleep for too long makes us feel terrible, and that getting a good night's sleep can make us feel ready to take on the world.

Scientists have gone to great lengths to fully understand sleep's benefits. In studies of humans and other animals, they have discovered that sleep plays a critical role in immune function, metabolism, memory, learning, and other vital functions. The features in this section explore these discoveries and describe specific ways in which we all benefit from sleep.

Why Do We Sleep, Anyway?

Although scientists aren't entirely sure why we sleep, they have many ideas about the functions of this mysterious part of our lives. While some of these functions may have deep evolutionary roots, others, such as sleep's potential role in memory and health, seem particularly relevant to life in the 21st century.

Sleep, Learning, and Memory

It may not be surprising that it is more difficult to take in new information following a night of inadequate or disturbed sleep. What’s more surprising is that it is just as important to get a good night’s sleep after learning something new in order to process and retain the information that has been learned.

How much sleep do I need?

The amount of sleep you need depends on several factors, including your age, lifestyle, health, and whether you have been getting enough sleep recently. The general recommendations for sleep are

During puberty, teenagers' biological clocks shift, and they are more likely to go to bed later than younger children and adults, and they tend to want to sleep later in the morning. This delayed sleep-wake rhythm conflicts with the early-morning start times of many high schools and helps explain why most teenagers do not get enough sleep.

Some people think that adults need less sleep as they age. But there is no evidence to show that seniors can get by with less sleep than people who are younger. As people age, however, they often get less sleep or they tend to spend less time in the deep, restful stage of sleep. Older people are also more easily awakened.

And it's not just the number of hours of sleep you get that matters. The quality of the sleep you get is also important. People whose sleep is frequently interrupted or cut short might not get enough of certain stages of sleep.

If you are wondering whether you are getting enough sleep, including quality sleep, ask yourself

What are the health effects of not getting enough sleep?

Sleep is important for overall health. When you don't get enough sleep (sleep deprivation), it does more than just make you feel tired. It can affect your performance, including your ability to think clearly, react quickly, and form memories. This may cause you to make bad decisions and take more risks. People with sleep deprivation are more likely to get into accidents.

Sleep deprivation can also affect your mood, leading to; 

Research shows that not getting enough sleep, or getting poor-quality sleep, increases your risk of;

Not getting enough sleep can also mean that you don't get enough of the hormones that help children grow and help adults and children build muscle mass, fight infections, and repair cells. Sleep deprivation magnifies the effect of alcohol. A tired person who drinks too much alcohol will be more impaired than a well-rested person.

How can I get better sleep?

You can take steps to improve your sleep habits. First, make sure that you allow yourself enough time to sleep. With enough sleep each night, you may find that you're happier and more productive during the day.

To improve your sleep habits, it also may help to;

See a doctor if you have continued trouble sleeping. You may have a sleep disorder, such as insomnia or sleep apnea. In some cases, your doctor may suggest trying over-the-counter or prescription sleep aid. In other cases, your doctor may want you to do a sleep study, to help diagnose the problem.

If you are a shift worker, it can be even harder to get a good sleep. 

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