Think of your daily activities. Which activity is so important you should devote one-third of your time to doing it? Probably the first things that come to mind are working, spending time with your family, or doing leisure activities. But there’s something else you should be doing – sleeping. Many people view sleep as merely “down time” when their brains shut off and their bodies rest.
In actuality, while you sleep your brain is hard at work forming the pathways necessary for learning and creating memories and new insights. Despite growing support for the idea that adequate sleep, like adequate nutrition and physical activity, is vital to our well-being, people are sleeping less. The nonstop “24/7” nature of the world today encourages longer or nighttime work hours and offers continual access to entertainment and other activities. To keep up, people cut back on sleep.
A common myth is that people can learn to get by on little sleep (such as less than 6 hours a night) with no adverse effects. However, research suggests that adults need at least 7–8 hours of sleep each night to be well rested. Growing evidence shows that a chronic lack of sleep increases your risk of obesity, diabetes, cardiovascular disease, and infections. Children and adolescents’ are also not sleeping enough which has been linked to increased exposure to electronic media. Lack of sleep may have a direct effect on children’s health, behavior, and development.
People may cut back on sleep, thinking it won’t be a problem, because other responsibilities seem much more important. But research shows that a number of aspects of your health and quality of life are linked to sleep, and these aspects are impaired when you are sleep deprived.
Your Learning, Memory, and Mood
Students who have trouble grasping new information or learning new skills are often advised to “sleep on it,” and that advice seems well founded. People can learn a task better if they are well rested and may better remember what they learned. Other studies suggest that it’s important to get enough rest the night before a mentally challenging task, rather than only sleeping for a short period or waiting to sleep until after the task is complete.
Exactly what happens during sleep to improve our learning, memory, and insight isn’t known. We suspect that while people sleep they form or strengthen the pathways of brain cells needed to perform these tasks. This process may explain why sleep is needed for proper brain development in infants.
Lack of sleep makes it harder to focus and pay attention and can make you more easily confused. Lack of sleep leads to faulty decision making, more risk taking, and slows down your reaction time, which is particularly important to driving and other tasks that require quick response. When people who lack sleep are tested on a driving simulator, they perform just as poorly as people who are drunk. The bottom line is: not getting a good night’s sleep can be dangerous!
2. Your Heart
Sleep gives your heart and vascular system a much-needed rest. During non-REM sleep, your heart rate and blood pressure progressively slow as you enter deeper sleep. During REM sleep, in response to dreams, your heart and breathing rates can rise and fall and your blood pressure can be variable. These changes throughout the night in blood pressure and heart and breathing rates seem to promote cardiovascular health.
If you don’t get enough sleep, the nightly dip in blood pressure that appears to be important for good cardiovascular health may not occur. Some sleep related abnormalities may also be markers of heart disease and increased risk of stroke. A lack of sleep puts your body under stress and may trigger the release of stress hormones during the day. These hormones keep your blood pressure from dipping during sleep, which increases your risk for heart disease.
3. Your Hormones
When you were young, your mother may have told you that you need to get enough sleep to grow strong and tall. She may have been right! Deep sleep (stage 3 non-REM sleep) contributes to growth in children and boosts muscle mass and the repair of cells and tissues in children and adults. Sleep’s effect on the release of sex hormones also contributes to puberty and fertility. Consequently, women who work at night and tend to lack sleep may be at increased risk of miscarriage.
Your mother was also probably right if she told you that getting a good night’s sleep on a regular basis would help keep you from getting sick and help you get better if you do get sick. Lack of sleep can reduce your body’s ability to fight off common infections.
Although lack of exercise and other factors also contribute, the current epidemic of diabetes and obesity seems to be related, at least in part, to chronically short or disrupted sleep or not sleeping during the night. Evidence is growing that sleep is a powerful regulator of appetite, energy use, and weight control. The less people sleep, the more likely they are to be overweight or obese and prefer eating foods that are higher in calories and carbohydrates.
Signs that your sleep is on track:
Here are some statements about sleep. If these apply to you, it’s a good sign that your sleep is on track.
- You fall asleep within 15-20 minutes of lying down to sleep.
- You regularly sleep a total of 7-9 hours in a 24-hour period.
- While in your bed, your sleep is continuous—you don’t have long periods of lying awake when you wish to be sleeping.
- You wake up feeling refreshed, as if you’ve “filled the tank.”
- You feel alert and are able to be fully productive throughout the waking hours (note, it’s natural for people to feel a dip in alertness during waking hours, but with healthy sleep, alertness returns).
- Your partner or family members do not notice any disturbing or out of the ordinary behavior from you while you sleep, such as snoring, pauses in breathing, restlessness, or otherwise nighttime behaviors.
Shift workers who try to sleep during the day often wake up after fewer than 7-9 hours, because of the alerting signals coming from their circadian system. This does not mean they don’t need 7-8 hours of sleep per day—it just means it’s harder to sleep during the day. Over time, this can lead to chronic sleep deprivation.
Click here to learn more about what makes you sleep, how much is enough, what disrupts sleep, and common sleep disorders.