Do humans really need to sleep at night?

Question

I've been trying to live more normally and go to bed at 12.00 a.m and wake up early in the morning for the past week but I don't feel so well.I get headaches and I don't feel very happy.

Do we really need to sleep at night,in the dark for a good health?Or can we live nocturnally,sleep at daytime and lead a healthy life?

Answer 1

Most humans need 6 hours of sleep so that the brain can unwind and get the body "refueled" with proper O2 supplies, etc.

Researchers once said thee body needs to spend 1/3 of our life in bed.

Now they are stipulating we only need 25% of that same time.

Answer 2

Yes- thats why we get tired and sleep during the night.

Answer 3

Yes I think everyone needs sleep what if you was awake all the time thinking of all your problems and worrys all the time! It would send me nuts this is why people need rest to get rid of worrys for a little while

Answer 4

Scientists have shown numerous ways in which sleep is related to memory. In a study conducted by Turner, Drummond, Salamat, and Brown[25] working memory was shown to be affected by sleep deprivation. Working memory is important because it keeps information active for further processing and supports higher-level cognitive functions such as decision making, reasoning, and episodic memory. Turner et al. allowed 18 women and 22 men to sleep only 26 minutes per night over a 4-day period. Subjects were given initial cognitive tests while well rested and then tested again twice a day during the 4 days of sleep deprivation. On the final test the average working memory span of the sleep deprived group had dropped by 38% in comparison to the control group.

Memory also seems to be affected differently by certain stages of sleep such as REM and slow-wave sleep (SWS). In one study cited in Born, Rasch, and Gais[26] multiple groups of human subjects were used: wake control groups and sleep test groups. Sleep and wake groups were taught a task and then tested on it both on early and late nights, with the order of nights balanced across participants. When the subjects' brains were scanned during sleep, hypnograms revealed that SWS was the dominant sleep stage during the early night representing around 23% on average for sleep stage activity. The early night test group performed 16% better on the declarative memory test than the control group. During late night sleep, REM became the most active sleep stage at about 24%, and the late night test group performed 25% better on the procedural memory test than the control group. This indicates that procedural memory benefits from late REM-rich sleep whereas declarative memory benefits from early SWS-rich sleep.

Another study conducted by Datta[27] indirectly supports these results. The subjects chosen were 22 male rats. A box was constructed where a single rat could move freely from one end to the other. The bottom of the box was made of a steel grate. A light would shine in the box accompanied by a sound. After a 5 second delay an electrical shock would be applied. Once the shock commenced the rat could move to the other end of the box, ending the shock immediately. The rat could also use the 5-second delay to move to the other end of the box and avoid the shock entirely. The length of the shock never exceeded 5 seconds. This was repeated 30 times for half the rats. The other half, the control group, was placed in the same trial but the rats were shocked regardless of their reaction. After each of the training sessions the rat would be placed in a recording cage for 6 hours of polygraphic recordings. This process was repeated for 3 consecutive days. This study found that during the post-trial sleep recording session rats spent 25.47% more time in REM sleep after learning trials than after control trials. These trials support the results of the Born et al. study, indicating an obvious correlation between REM sleep and procedural knowledge.

Another interesting observation of the Datta study is that the learning group spent 180% more time in SWS than did the control group during the post-trial sleep-recording session. This phenomenon is supported by a study performed by Kudrimoti, Barnes, and McNaughton.[28] This study shows that after spatial exploration activity, patterns of hippocampal place cells are reactivated during SWS following the experiment. In a study by Kudrimoti et al. seven rats were run through a linear track using rewards on either end. The rats would then be placed in the track for 30 minutes to allow them to adjust (PRE), then they ran the track with reward based training for 30 minutes (RUN), and then they were allowed to rest for 30 minutes. During each of these three periods EEG data were collected for information on the rats’ sleep stages. Kudrimoti et al. computed the mean firing rates of hippocampal place cells during pre-behavior SWS (PRE) and three 10-minute intervals in post-behavior SWS (POST) by averaging across 22 track-running sessions from seven rats. The results showed that 10 minutes after the trial RUN session there was a 12% increase in the mean firing rate of hippocampal place cells from the PRE level, however after 20 minutes the mean firing rate returned rapidly toward the PRE level. The elevated firing of hippocampal place cells during SWS after spatial exploration could explain why there were elevated levels of SWS sleep in Datta’s study as it also dealt with a form of spatial exploration.

The different studies all suggest that there is a correlation between sleep and the many complex functions of memory.

Answer 5

It doesn't matter so much WHEN you sleep but yes, you need sleep if you are like most humans or other animals.   I think it may have restorative functions for the brain, and may also have physiological ramifications in other parts of the body.  Sleep deprivation experiments lead to hallucinations and death in experimental animals and human subjects.  Something goes wrong with the body's thermoregulatory system as well.  

Answer 6

We are definitely designed to sleep at night.  I even read recently that scientists were considering making jobs that have people up all night (nurses, doctors, factory workers etc) carry an increased risk of cancer label.  They discovered that going against your natural sleep cycles disrupts your body in ways previously unknown.  

Answer 7

Humans are diurnal animals. We're typically active during the day and resting during the night.

Answer 8

Some people think that we rest during our sleep, and that without sleeping we would be tired, and get sick.

In contrast, experiments with dogs as well as polyphasic sleepers have shown that it is not sleep that we need, but REM dreams. Dogs have died when prevented from dreaming, but not when prevented from sleeping. Polyphasic sleepers get by fine with 3 hours a day of mostly dream sleep.

However, there is a guy in vietnam who has been without any sleep for 30 years! He is active and in good health. Is he lucky genetically? Or is it something he learned? This means that not sleeping does not necessarily lead to death or bad health. We just need to figure out how to get rid of sleeping.

Although many factors influence how much sleep you really need, most young adults report sleeping about seven and a half hours on weekday nights and eight and a half hours on weekend nights. And the common recommendation is eight hours a night. But individual needs vary greatly. There are so-called short-sleepers and long-sleepers -- those who need as little as five and a half hours to as much as about nine and a half hours.

How much sleep you require depends on several factors including:

    * Your inherited genetic need

    * Your sleep hygiene (those daily activities you control, from drinking coffee or alcohol to smoking and exercise)

    * The quality of your sleep

    * Your 24-hour daily cycle known as the circadian rhythm

For example, smoking, drinking, and exercise can affect your sleep dramatically. What you actually do in bed (like reading or watching TV) and how much exposure to light you have (looking at that bright computer screen 'til midnight) will also significantly alter both the quality and quantity of your sleep. They all interact to determine how long you need to sleep to wake up feeling refreshed and remain alert throughout the day.

How did we get the age-old recommendation that we need a solid eight hours of sleep? In a classic study, researchers placed a volunteer in windowless, light-controlled room for 30 days. The light was on for 16 hours and off for eight hours, but the study participant could also turn the lights on and off at will.

Before the experiment began, the subject routinely got about six and a half hours of sleep. During the first night of the experiment he slept eight hours, the second night 10 hours, the third night 12 hours, and the fourth night 14 hours. Over the next several days, he began to reduce the number of hours slept, eventually falling to a steady eight hours and 13 minutes. This experiment was performed repeatedly with all types of people, with similar results, and this is where the recommendation of eight hours comes from.

Your Sleep Debt

OK, so how do you determine how much sleep you really need?

First, let's look at your bank account -- your sleep bank account, that is -- and see if you have a debt to pay. Throughout the day, you take out about eight hours from this account, generating a sleep debt. Over the course of the night, as you snooze, you replenish your account. If you sleep only, say, six and a half hours, you still owe one and a half hours. If you do this for five nights in a row, you have lost an entire night's sleep! You will then need extra sleep over the next few days to replenish your sleep debt.

How much sleep do you get -- do you have a sleep debt? Do this simple test: Starting on a Sunday, do not drink alcohol or caffeine; do not smoke; go to sleep about the same time every night; and get an uninterrupted seven to eight hours of sleep for the next six nights. Then, on Saturday morning, sleep in. See how long your body will let you sleep. If you sleep longer than you did during the week -- then you have a sleep debt. So you should consider getting more sleep each night to replenish that sleep debt. Hey, not so easy, you say. Well, give it a try and do the best you can. Why?

Not getting the proper amount of and the best quality sleep may have serious consequences. Many studies have shown that sleep deprivation adversely affects performance and alertness. Reducing sleep by as little as one and a half hours for just one night reduces daytime alertness by about one-third. Excessive daytime sleepiness impairs memory and the ability to think and process information, and contributes to a substantially increased risk of sustaining an occupational injury.

The bottom line is that you should wake up feeling relatively refreshed, and you should generally not feel sleepy during the day. If this is not the case, you may have an unrecognized sleep disorder and should see your doctor or a sleep specialist.  

Answer 9

hmm. well supposedly humans aren't meant for nocturnal living so we tend to, slip mentally. but, i've been living a nocturnal life since i was young. still am. hence me being up still. seriously i still haven't slept lol. just depends on what you're used to. usually it's people's job that decides their sleep habits. me, i hate morning. not a morning person at all. i don't even feel awake and energized till noon anymore