About Sleep (II part)

Why sleep is good for you and skimping on it isn't

Does it really matter if you get enough sleep? Absolutely! Not only does the quantity of your sleep matter, but the quality of your sleep is important as well. People whose sleep is interrupted a lot or is cut short might not get enough of certain stages of sleep. In other words, how well rested you are and how well you function the next day depend on your total sleep time an dhow much of the various stages of sleep you get each night.

Performance: We need sleep to think clearly, react quickly, and create memories. Inf act, the pathways in the brain that help us learn and remember are very active when we sleep. Studies show that people who are taught mentally challenging tasks do better after a good night's sleep. Other research suggests that sleep is needed for creative problem solving.
Skimping on sleep has a price. Cutting back by even 1 hour can make it tough to focus the next day and can slow your response time. Studies also find that when you lack sleep, you are more likely to make bad decisions and take more risks. This can result in lower performance on the job or in school and a greater risk for a car crash.

Mood: Sleep also affects mood. Insufficient sleep can make you irritable and is linked to poor behavior and trouble with relationships, especially among children and teens. People who chronically lack sleep are also more likely to become depressed.

Health: Sleep is also important for good health. Studies show that not getting enough sleep or getting poor quality sleep on a regular basis increases the risk of having high blood pressure, heart disease, and other medical conditions.

In addition, during sleep, your body produces valuable hormones. Deep sleep triggers more release of growth hormone, which fuels growth in children, and helps build muscle mass and repair cells and tissues in children and adults. Another type of hormone that increases during sleep works to fight various infections. This might explain why a good night's sleep helps keep you from getting sick—and helps you recover when you do get sick.
Hormones released during sleep also affect how the body uses energy. Studies find that the less people sleep, the more likely they are to be overweight or obese, to develop diabetes, and to prefer eating foods that are high in calories and carbohydrates.

It's about time

How sleepy you are depends largely on how well you've been sleeping and how much sleep you've been getting. Another key factor is your internal "biological clock"—a tiny bundle of cells in your brain that responds to light signals through your eyes and promotes wakefulness. Because of the timing of the biological clock and other bodily processes, you naturally feel drowsy between midnight and 7 a.m. and again in the midafternoon between 1 p.m. and 4 p.m.

Night shift workers often find themselves drowsy at work. They also have trouble falling asleep or staying asleep during the day, when their schedules require them to sleep. Being sleepy puts them at risk for injuries on the road and at work. Night shift workers are also more likely to have conditions such as heart disease, digestive disorders, and infertility, as well as emotional problems. All of these problems may be related, at least in part, to their chronic lack of sleep.

Adapting to a new sleep and wake times can also be hard for travelers crossing time zones, resulting in what's known as jet lag. Jet lag can lead to daytime sleepiness, trouble falling asleep or staying asleep at night, poor concentration, and irritability.The good news is that by using appropriately timed cues, most people can change their biological clock, but only by 1–2 hours per day at best. Therefore, it can take several days to adjust to a new time zone (or different work schedule). If you'll be moving across time zones, you might want to begin adapting to the new time zone a few days before leaving. Or, if you are traveling for just a few days, you might want to stick with your original sleep schedule and not try to adjust to the new time zone.