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Questions tagged [sleep]

The biological process characterized by reversible unconsciousness, unresponsiveness to external stimuli and motor passivity.

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Is it possible for a human being to live on a different day cycle?

I am considering writing a story where a character lives on a 30-hour day cycle. That is, this person sleeps for 9.5 hours and is awake for 20.5 hours. Then this person repeats the schedule. I'd ...
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If mammals evolved to be nocturnal, then how did we get so staunchly diurnal in such short time?

Much of human health revolves around sleeping well through the night. We know about circadian and body temperature rhythms which make us sleepy at night, peak melatonin production in the middle of ...
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127 views

Why do we fall asleep when our eyes are closed?

Why do we fall asleep when our eyes are closed? When we lie down with our eyes closed, eventually we'll fall asleep. Why is that? Is our eyes closing some sort of trigger to our brain that says it's ...
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754 views

How loud a sound would need to be to wake someone up?

I have been researching about this and it looks like the term would be auditory arousal threshold. Imagine you fall asleep while listening to music with earbuds. Out of a sudden, the device starts ...
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Would an h1 Full Agonist Prevent Sleep

According to Wikipedia the h1 receptors stop firing to effectively manage sleep. Assuming I understand how blocking and non blocking receptors work would a full agonist on the h1 receptors ...
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72 views

Can low melatonin levels and/or LED lights cause or exacerbate macular degeneration?

I have two questions that may or may not be interconnected. My first question is: Does melatonin prevent macular degeneration? Could low melatonin levels (caused by blue-rich light exposure in the ...
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22 views

Delay of sleeping on cortisol cycle

I was told that cortisol has to be measured at 9am or 4pm, because those where its peak level. But I wonder if changes on sleep patters affect the cortisol cycle. I mean, if I usually go to sleep ...
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Sound volume drop when falling asleep in an airplane

Note: This question has nothing to do with pressure change. When I'm flying in an aircraft at cruising altitude, the monotonous sound often lulls me to sleep. I've noticed that just as I am on the ...
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188 views

Melatonin production, sleep, and “cyan light”; how might this finding be possible?

The BBC News article Cyan colour hidden ingredient in sleep describes research that suggests melatonin levels as measured in saliva could be affected by the presence or absence of cyan color in a ...
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Can varied temperature while sleeping help quality of sleep?

I read an interesting article which is about relations between body temperature and quality of sleep. I'm interested in the phrase from the article. Other experiments that varied the ambient ...
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43 views

Does the brain always enter alpha/beta waves upon brief awakenings during the night?

If you realize you are awake briefly before falling back asleep, have you necessarily exited REM sleep or another stage? That is, is the experience of waking briefly (tossing and turning, etc.) always ...
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110 views

What is “integrated spindle activity” in plain English?

From a research article: To determine if a combination of spindle parameters allowed for a better group discrimination, integrated spindle activity (ISA) was calculated by integrating over time ...
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1answer
218 views

Breathing with Clogged Nose during Sleep

This just happened to me recently, I was trying to sleep with clogged nose, so I tried breathing through my mouth. As you can imagine it was hard, but I managed to sleep deeply. So I became curious, ...
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369 views

What is the exact frequency of Delta brain waves during Slow Wave NREM Sleep?

I saw a TED talk about researchers playing pulsating pink noise while a test subject is in Stage 3 Non-REM / Slow Wave / Deep sleep and observing an increase in Delta wave EEG activity. This seems to ...
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108 views

Why is Sleep apnea only risk to males?

I was reading this article. In Risk Factors, it clearly mention "Being a male". Why is Sleep apnea only risk to males?
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73 views

Do Vaccinium membranaceum plants need a minimum amount of darkness per 24 hours?

I have Vaccinium membranaceum (black huckleberry) seedlings growing in a greenhouse. I have the option of providing fluorescent light to the plants 24 hours a day. However, it has occurred to me that ...
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1k views

Is it possible to have sleep paralysis while sleepwalking?

At least from a conceptual level, these two disorders don't conflict. The effect of sleep paralysis is being conscious while having the inability to consciously direct motor functions. Sleepwalking is ...
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242 views

What in the brain has gone awry during sleep paralysis?

I experience episodes of what I assume is sleep paralysis (lasting ~ 10-30 seconds) a few times a year, where I'm conscious of being somewhat awake but unable to move. I can hear, but not see, and am ...
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387 views

Can our body adapt to periodic fluctuations in sleep?

Suppose that if I've to attend a morning class then I must wake at 5 AM in morning. Next, if I don't (attend the class) then I wake up at 7-8 AM. I've experienced that, since I do attend those ...
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524 views

Why do we need to close eyes to sleep?

Out of all our sensory organs, we need to stop taking signals explicitly only from eyes in order to sleep. Even interestingly, those who are not able to receive signals from eyes (i.e., the visually ...
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How does heart rate change when entering N1 sleep?

I would like to know how the heart rate changes as a person enters N1 (NREM 1) sleep from a wakeful state. The focus is on entering N1, and it would be great to have time-series data to see the ...
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436 views

Is there a difference between sleeping late and waking up late vs sleeping early and waking up early?

For example, if I sleep at 1 AM and wake up at 10 AM, will it negatively affect my health opposed to sleeping at 10 PM and waking up at 7 AM?
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96 views

Names for effects of sleep deprivation on the brain & body

When staying awake for a long period (3 or 4 days), some weird phenomena can occur. In my experience, it was always triggered by thinking too deeply and has in other occasions too. Do these things ...
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1answer
107 views

What causes sleep inertia?

Sometimes after a nap, I wake up in a state of grogginess. I learned that this is actually called sleep inertia. I'm able to find lots of methods to overcome this, but what causes it in the first ...
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115 views

Origin of melatonin: oxidative stress defense OR circadian rhythm?

Question Which functional role of melatonin came first? Regulation of the circadian rhythm Defense against oxidative stress Other Background I was well aware of the important role melatonin plays ...
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Longest lived land mammal when subtracting sleeping time?

Recently, it has been found that wild elephants only sleep two hours per night. Wild elephants also live quite long, the median life span is 56 years. Now, 56 years lived with 2 hours sleep per day ...
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167 views

What is the term for awareness of or inclusion of real sounds within a dream?

I fell asleep while listening to a podcast, and I am sure I was dreaming but I could also still hear the podcast. The podcast played an important role in the dream, I was searching for the source of ...
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2k views

Can adenosine be cleared?

I've been thinking about this question for awhile, since reading this question: What causes adenosine build up in the brain when awake? We know that a couple of things will block adenosine receptors: ...
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225 views

What is blue light?

What is the "blue light" often discussed in relation to human melatonin production, sleep/wake cycles, etc.? A Google search seems to define it as light of a particular wavelength, suggesting that it ...
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1k views

Is it better to maximize sleep, or align to ~1.5 hr cycles

What is better for the body, to sleep 6 hours (4 deep sleep cycles) or to sleep 7 hours, but interrupting the last sleep cycle. I know I feel a lot better with 6, but am curious as to its medical ...
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How can a powernap boost memeroy and cheerfulness?

Background A power nap is a short sleep which terminates before the occurrence of deep sleep or slow-wave sleep (SWS), intended to quickly revitalize the subject. (wiki) The results of ...
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66 views

Does the effect of light on melatonin release adapts to light level over long periods of time?

Or do you go to bed with low levels of melatonin when you stay behind a computer screen all day?
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1k views

Why do some people become more aggressive when tired?

Why do some people become more aggressive when they are tired? I've been thinking about this question for a few days and my 'hypothesis' is that the neural activity in the prefrontal cortex lessens as ...
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To what extent is excretory control a learned vs. instinctive behavior?

Human babies are clearly not born knowing whether/how to hold in urine and feces, and teaching them to do so requires a nontrivial (really nontrivial...) amount of work on the parents' part. But once ...
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107 views

Is 8 hours of sleep necessary?

Many studies claim that humans need 8 hours of sleep. During sleep there are several different stages, from stage 1 to 4 as well as REM sleep. However, are all these stages actually necessary? If yes, ...
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360 views

Effect of sleep deprivation on pupils and pupillary responses

What is the effect, if any, of sleep deprivation on pupils? Specifically: Are pupils more dilated/constricted? Is the pupillary response to light any different? Anything else?
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1answer
771 views

Why do we feel sleepy when we wake up

Why do we feel sleepy, tired, and feel like we need to sleep more when we wake up? (Like, is there a special chemical in the brain that causes that?). Are there any ways to wake up without feeling ...
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2k views

Is there a link between digestion and nightmares?

A common belief is that eating too much before going to sleep can cause to have nightmares. In fact, I often experience it: I systematically have nightmares after eating too much in the evening. ...
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Why do I drop my pen in a drowsy lecture?

I know that there is loss of muscle tone during REM sleep. Is this loss in muscle tone the reason I generally drop my pen in a sleepy lecture? But we were taught that sleep has 4 stages and REM sleep ...
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220 views

Does night sleep provide more energy-regain than sleep during the day? [closed]

After reading this, I know that sleeping is an universal function, and that basically everything with a brain has the need to sleep. However, I am still confused to what extent it is necessary to ...
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759 views

Why do we sleep?

While we do know that the human body is regulated by a circadian clock that keeps humans on a sleep/wake cycle, we don’t really know why. Sleep is the time when our bodies repair tissues and perform ...
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1answer
5k views

How does waking up from an alarm clock work?

During sleep, one's brain is shut down. All it can do is to see some dreams from the semi-conscious mind. Then how does it hear when the alarm clock rings?
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170 views

How does the brain manifest and realize the intention to resist sleep?

The question title says it all. What happens in my brain when I resist sleep? I would appreciate explanations on neurotransmitter changes, what areas of the brain activate to resist sleep, what can an ...
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8k views

What's the technical difference between fainting (and being unconscious) and falling asleep (and sleeping)?

This is actually a popular question along google results but the answers usually sound like: sleep is voluntary (oh is it?) and healthy fainting is result of accident and is not normal I read those ...
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55 views

Can body temperature affect the quality of sleep?

If so, how does it influence our sleep? And what can we do to improve the quality of sleep by adjesting our body tempurature?
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1answer
872 views

Do deaf people sleep better?

Since deaf people can't hear, is relaxing and falling asleep easier for them? In general, do they sleep better than hearing people? Of course some hearing people have no trouble getting to sleep, but ...
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1answer
184 views

Is the immune system suppressed during sleep?

Of course we have heard that during stress our immune system is suppressed. This leads me to wonder, does the immune system get suppressed when we are sleeping and why? During both these conditions ...
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119 views

Why do some medicines induce sleep? [closed]

I have seen lot of people sleep or say that they are feeling sleepy after taking some medicines. Why? I mean, if a medicine acts on some cell of the body because that cell has got its receptors and ...
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1answer
3k views

Can you recharge without sleeping? [closed]

Sometimes it's difficult falling asleep for almost an entire night. You might feel like getting up and being productive instead, or 'pull an all-nighter'. Or you can try to simply lay in bed to relax ...
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325 views

External sensory stimuli that awaken a person from sleep

An external sound or touch can awaken someone. Can a light? It would have to be very strong, but part of the reason might be that it would have to penetrate the eyelids. And can a smell or taste? ...