How many hours of sleep is necessary for the human body and why?
965466
6 to 8 hours of sleep is necessary for the human body.  \n\nIts Importance:\n\nSleep is a natural part of everybody's life, but many people know very little about how important it is, and some even try to get by with little sleep. Sleep is something our bodies need to do; it is not an option. Even though the exact reasons for sleep remain a mystery, we do know that during sleep many of the body's major organ and regulatory systems continue to work actively. Some parts of the brain actually increase their activity dramatically, and the body produces more of certain hormones.\n\nSleep, like diet and exercise, is important for our minds and bodies to function normally. In fact, sleep appears to be required for survival. Rats deprived of sleep die within two to three weeks, a time frame similar to death due to starvation.\n\nAn internal biological clock regulates the timing for sleep. It programs each person to feel sleepy during the nighttime hours and to be active during the daylight hours. Light is the cue that synchronizes the biological clock to the 24-hour cycle of day and night.
358621
The amount of sleep needed varies from person to person but most require 8 hours.  You should sleep at least the number of hours it takes for you to wake up feeling rested and refreshed. For some people, this is 6 hours, for others, it is 10.  You have to find out what works for you.
1174820
You may not be getting enough sleep.  It's a common misconception that everyone needs 8 hours.  Some people need more and some need less.  Try going to bed earlier.
118982
The most anyone can sleep is most definitely NOT 8hrs. I have had friends who slept for 24hrs straight. It all depends on how much of a "sleep deficit" you have. \nYour body needs a certain amount of sleep, and that differs for everyone. However, it is recommended that we get around 8hrs per night if we are to function at our best. \nSleep is important for many reasons - helps with "solidifying" your experiences and memories that you have from the previous day, recharges you with energy - I think it's pretty obvious. \nAbout the day vs night sleep? It is best to sleep during the dark hours because the production of MELATONIN - a hormone that regulates sleep-wake cycles - varies with exposure to light. \nI also happen to be "nocturnal", but this is causing me a lot of problems. I cannot imagine how it would feel like to wake up feeling refreshed before 11am!
1115730
You should be getting at least 7-9 hours of sleep. I have to have my sleep or I am no good to anyone-at all.
1133904
Don't worry about the number of hours you're sleeping; think about how you feel in the morning, as well as how easily you get tired as the day goes on.  If you're comfortable with your level of energy, then that's the right amount of sleep for you.  And of course, it can change depending on how physically & mentally active you are.  In addition, the average person needs less sleep as they get older.
221264
The record is something like 12 days or so by a kid. Everyone will eventually succumb to the need to sleep but when in the question. They cannot figure out why our body needs sleep and one one has ever died from a lack of it. Some theorize that we sleep because back in the day humans needed to stay in at night to avoid getting killed by nocturnal animals.
92433
It really depends on your own needs - some people take naps during the day, others just naturally need more or less sleep.  I have a friend who could sleep 12-16 hours a day if she let herself.  If you find yourself sleeping more than you want, you should be able to slowly change your sleep patterns to something that works better for you.
863947
Adult requires a minimum sleep of 6 hours a day, sleeps will seriously effect your health in a very big way, if you do not get enough sleep, your anxienty, stress level will increase with ease, your mind will not think properly and also that your health will deteriorate extremely fast. so please try not to sleep at the minimum of 6 hours, get a healthy 8 to 9 hours. \n\nIn Korea this guy died of being awake for 50 straight hours playing online game. A few cases has happend already. so Take care Cheers
1136626
Not enough in general. We need good six hours sleep .\nAlso your age sex your physical conditions the type of work , all play a role. How can I pilot or driver be continuously exposed to short periods of sleep and endangering the life of many.\nIf you are enjjoying holidays and watching WORLD CUP FOOT BALL MATCH DAILY LATE IN THE NIGHT AT PLACES LIKE ASIA then less sleep, intemittent sleep during night and a day time nap is ok. You cant help it. We get to watch such matches once in four years and there is thrill in watching LIVE not recorded and replayed
717918
Ideally you should get 7-8 hours of sleep. Sleep deprivation leads to hypertension (high blood presure), depression, not functioning at your full level. If you must get by on little amounts of sleep, 20minute naps can be very refreshing if you can find that time. Make sure you are taking a multivitamin and if you are extremely tired try a caffeine pill but beware when that wears off you will suddenly be extremely tired and your body will crash. 6 hours of sleep a night is minimum. YOu can actually die from exhaustion from not getting enough sleep. Psychologists have done studies that have shown different levels of sleep  deprivation have lead to psychosis and have even resembled people that should be put in a mental health unit.
973807
Although it’s a common belief that 8 hours of sleep is required for optimal health, a six-year study of more than one million adults ages 30 to 102 has shown that people who get only 6 to 7 hours a night have a lower death rate. Individuals who sleep 8 hours or more, or less than 4 hours a night, were shown to have a significantly increased death rate compared to those who averaged 6 to 7 hours.\n\nResearchers from the University of California, San Diego (UCSD) School of Medicine and the American Cancer Society collaborated on the study, which appeared in the February 15, 2002 issue of the Archives of General Psychiatry, a journal of the American Medical Association.\n\nAlthough the data indicated the highest mortality rates with long-duration sleep, the study could not explain the causes or reasons for this association.\n \nDaniel F. Kripke, M.D., in his sleep lab at UCSD.\n \nFirst author Daniel F. Kripke, M.D., a UCSD professor of psychiatry who specializes in sleep research, said “we don’t know if long sleep periods lead to death. Additional studies are needed to determine if setting your alarm clock earlier will actually improve your health.”\n\nBut, he added “individuals who now average 6.5 hours of sleep a night, can be reassured that this is a safe amount of sleep. From a health standpoint, there is no reason to sleep longer.”\n\nKripke is also a member of UCSD's Sam and Rose Stein Institute for Research on Aging.\n\nThe study, which addressed sleep issues as part of the Cancer Prevention Study II (CPSII) of the American Cancer Society, also indicated that participants who reported occasional bouts of insomnia did not have an increased mortality rate, but those individuals who took sleeping pills were more likely to die sooner.\n\n“Insomnia is not synonymous with short sleep,” the authors said in the article. “Patients commonly complain of insomnia when their sleep durations are well within the range of people without sleep symptoms.”\n\nThey added that physicians believe most patient complaints about “insomnia” are actually related to depression, rather than a diagnosis of insomnia.\n\nWith 1.1 million participants, this was the first large-scale population study of sleep to also take into consideration variables such as age, diet, exercise, previous health problems, and risk factors such as smoking, in comparing longevity among the participants. In other words, individuals with specific characteristics were compared with individuals of a similar age, health background, etc.\n\nAlthough the study was conducted from 1982-88, the sleep results have not been available until recently due to the length of time required to input and analyze the vast amount and variety of data from the 1.1 million participants.\n\n“Previous sleep studies have indicated that both short- and long-duration sleep had higher mortality rates,” Kripke said. “However, none of those studies were large enough to distinguish the difference between 7 and 8 hours a night, until now.”\n  \nThe figures above indicate hours of sleep for men (left) and women (right). The hazard ratio, the top bar graph, indicates the mortality risk while the bottom graph shows the percentage of subjects associated with the reported number of hours sleep.\n \n The best survival rates were found among those who slept 7 hours per night. The study showed that a group sleeping 8 hours were 12 percent more likely to die within the six-year period than those sleeping 7 hours, other factors being equal. Even those with as little as 5 hours sleep lived longer than participants with 8 hours or more per night.\n\nThe mean age for women in the study was 57, while the mean age for men was 58. Within the six year period, 5.1 percent of the women had died and 9.4 percent of the men. The causes of death resembled the distribution for the general population.\n\nAdditional authors of the study were Lawrence Garfinkel, M.A., the American Cancer Society, New
102194
For most adults, yes.  I think a lot of people sleep too much, either because they are avoiding life, or because they are wearing themselves out in the daytime.  Did you know, by the way, that if you nap in short segments, you need less total sleep time?  Try taking a nap soon after dinner, for an hour or two, and then stay up until you are really sleepy.  Even if you have to get up to an alarm clock in the wee small hours of the morning, you will probably be more refreshed than if you went to bed approximately 7 to 8 hours before the alarm is due to go off.\n\nRemember, too, that wake/sleep cycles are as individual as everything else about human beings.  We can learn something from the ways of others, but ultimately we must each find what makes us feel the best.  Life is an experiment, and you are your own guinea pig.
245238
9 hours is actually a very healthy amount to sleep. If you can, why not? 6 hours is too little
589112
Depends on your activity level etc. most people need 7-8 hours but some functon well one 4-5 also . decide how many hours at which you feel your best .
85308
Various biological factors help determine how long people can last without sleeping. Some people can go for longer periods of time than others. \n\nNotorious cases of record-setters include disc jockey Peter Tripp who in 1959 stayed up for more than eight days as a promotional stunt. After a few days, he began to hallucinate, seeing kittens, mice, and cobwebs. He also became paranoid, insisting that an electrician had dropped a hot electrode into his shoe.\n\nSix years later, high school student Randy Gardner attempted to break the Guinness Book of World Records for the longest time awake -- 260 hours. And after 11 days without sleep he suffered no hallucinations or paranoia and no psychotic symptoms.\n\nSome people with severe insomnia claim to have gone for several weeks without sleep. Though ususally in cases like this, even though they appear awake, their brain actually goes into a light sleep-like state.
229824
Schools used to say seven to eight hours.  Now they are saying eight to nine hours.  I feel you should sleep as much as you feel you need to.  sometimes I only need to sleep three or four hours... sometimes I will sleep eleven hours.