Many people view sleep as merely a “down time” when their brains shut off and their bodies rest. 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 vital tasks carried out during sleep help people stay healthy and function at their best. While you sleep, your brain is hard at work forming the pathways necessary for learning and creating memories and new insights.
Without enough sleep, you can’t focus and pay attention or respond quickly. A lack of sleep may even cause mood problems. Also, growing evidence shows that a chronic lack of sleep increases your risk of obesity, diabetes, cardiovascular disease, and infections.
Sleep is a time when your body and brain shut down for rest and relaxation. No evidence shows that any major organ (including the brain) or regulatory system in the body shuts down during sleep.
Some physiological processes actually become more active while you sleep. For example, secretion of certain hormones is boosted, and activity of the pathways in the brain linked to learning and memory increases.
Getting just 1 hour less sleep per night than needed will not have any effect on your daytime functioning. This lack of sleep may not make you noticeably sleepy during the day. But even slightly less sleep can affect your ability to think properly and respond quickly, and it can impair your cardiovascular health and energy balance as well as your body’s ability to fight infections, particularly if lack of sleep continues.
If you consistently do not get enough sleep, a sleep debt builds up that you can never repay. This sleep debt affects your health and quality of life and makes you feel tired during the day.
Your body adjusts quickly to different sleep schedules. Your biological clock makes you most alert during the daytime and least alert at night. Thus, even if you work the night shift, you will naturally feel sleepy when nighttime comes.
Most people can reset their biological clock, but only by appropriately timed cues — and even then, by 1 to 2 hours per day at best. Consequently, it can take more than a week to adjust to a substantial change in your sleep — wake cycle — for example, when traveling across several time zones or switching from working the day shift to the night shift.
People need less sleep as they get older. Older people don’t need less sleep, but they may get less sleep or find their sleep less refreshing. That’s because as people age, the quality of their sleep changes. Older people are also more likely to have insomnia or other medical conditions that disrupt their sleep.
Extra sleep for one night can cure you of problems with excessive daytime fatigue. Not only is the quantity of sleep important, but also the quality of sleep. Some people sleep 8 or 9 hours a night but don’t feel well rested when they wake up because the quality of their sleep is poor.
A number of sleep disorders and other medical conditions affect the quality of sleep. Sleeping more won’t lessen the daytime sleepiness these disorders or conditions cause. However, many of these disorders or conditions can be treated effectively with changes in behavior or with medical therapies. Additionally, one night of increased sleep may not correct multiple nights of inadequate sleep.
You can make up for lost sleep during the week by sleeping more on the weekends. Although this sleeping pattern will help you feel more rested, it will not completely make up for the lack of sleep or correct your sleep debt. This pattern also will not necessarily make up for impaired performance during the week or the physical problems that can result from not sleeping enough. Furthermore, sleeping later on the weekends can affect your biological clock, making it much harder to go to sleep at the right time on Sunday nights and get up early on Monday mornings.
Naps are a waste of time. Although naps are no substitute for a good night’s sleep, they can be restorative and help counter some of the effects of not getting enough sleep at night. Naps can actually help you learn how to do certain tasks quicker. But avoid taking naps later than 3 pm, particularly if you have trouble falling asleep at night, as late naps can make it harder for you to fall asleep when you go to bed.
Also, limit your naps to no longer than 20 minutes, because longer naps will make it harder to wake up and get back in the swing of things. If you take more than one or two planned or unplanned naps during the day, you may have a sleep disorder that should be treated.
Snoring is a normal part of sleep. Snoring during sleep is common, particularly as a person gets older. Evidence is growing that snoring on a regular basis can make you sleepy during the day and increase your risk for diabetes and heart disease. In addition, some studies link frequent snoring to problem behavior and poorer school achievement in children. Loud, frequent snoring also can be a sign of sleep apnea, a serious sleep disorder that should be evaluated and treated.
Children who don’t get enough sleep at night will show signs of sleepiness during the day. Unlike adults, children who don’t get enough sleep at night typically become hyperactive, irritable, and inattentive during the day. They also have increased risk of injury and more behavior problems, and their growth rate may be impaired. Sleep debt appears to be quite common during childhood and may be misdiagnosed as attention-deficit hyperactivity disorder.
The main cause of insomnia is worry. Although worry or stress can cause a short bout of insomnia, a persistent inability to fall asleep or stay asleep at night can be caused by a number of other factors. Certain medications and sleep disorders can keep you up at night.
Other common causes of insomnia are depression, anxiety disorders, and asthma, arthritis, or other medical conditions with symptoms that tend to be troublesome at night. Some people who have chronic insomnia also appear to be more “revved up” than normal, so it is harder for them to fall asleep.