Hot answers tagged

60

A quick search on Web of Science yields "Polyphasic Wake/Sleep Episodes in the Fire Ant, Solenopsis Invicta" (Cassill et al., 2009, @Mike Taylor found an accessable copy here) as one of the first hits. The main points from the abstract: Yes, ants sleep. indicators of deep sleep: ants are non-responsive to contact by other ants and antennae are folded ...


52

There have been some studies directly linking sleep deprivation to increased risk of catching a cold ("Behaviorally Assessed Sleep and Susceptibility to the Common Cold Sleep". 2015;38:1353–9.). Colds are caused by a family of viruses. There is pretty solid evidence that sleep deprivation has a significant weakening effect on your immune system. Given a ...


37

The short answer is apparently yes. Studies on sleep in insects date back to papers published by Phil and Nellie Rau in 1916 and 1938. Hussaini et al. (2003) showed that sleep does affect memory formation in honey bees. They showed that retention of extinction learning is significantly reduced in bees that were sleep-deprived. More about sleep in honeybees ...


19

A new study published in this week's journal SLEEP finds that people who sleep less than six hours are more likely to catch a cold. Researchers tracked 164 healthy men and women for a week at a time, monitoring how much they slept and exposing them to the rhinovirus, also known as, the common cold. Aric Prather, lead author of the study, and his colleagues ...


16

Based on various comments, I've expanded this answer. Though long, I cannot cover the depth of the topic of sleep but I tried to address the issues asked in the original question while broadly highlighting various aspects about sleep research. I welcome any suggestions for improvement. What is sleep? To know what it means to be awake, you must know what it ...


14

Sneezing does not occur during REM sleep, due to REM atonia.(1) The coughing reflex is also suppressed during sleep, but coughing may still occur occasionally during sleep. (2).


11

24 Hour Mark The consequences of sleep deprivation at 24 hours is comparable to the cognitive impairment of someone with a blood-alcohol content of 0.10 percent, according to a 2010 study in the International Journal of Occupational Medicine and Environmental Health. 36 Hours Now your health begins to be at risk. High levels of inflammatory markers ...


10

Short answer Sleep negatively impacts attention, which in turn impairs balance control in cognitively challenging situations. Background Schlesinger et al. (1998) argue that under normal conditions, postural control appears to be automatic, and to require little or no attention in young, healthy adults during quiet standing with full sensory input. However, ...


9

Well, you may want to re-state your question. There are numerous multi-cellular organisms without a nervous system. So you could say that they never sleep: sponges, plants, mushrooms. This paper on the evolution of sleep concludes: A phylogenetic evaluation of sleep demonstrates that all mammals, birds, and reptiles engage in sleep, and evidence for ...


9

The answer is of interest not only in sleep but also the perceptions of patients under anesthesia, comatose states, etc. Our senses aren't 'dimmed' in sleep. There is no effective way to turn off our senses. The best way to explain what happens in sleep is that at some point (the last point, actually), our cognitive processing of sensations changes. That is, ...


9

We don't actually know. But these two theories are strong candidates: Sleep 'cleans' the brain of toxins. Metabolic waste products of neural activity are cleared out of the sleeping brain at a faster rate than during the awake state. This finding suggests a mechanistic explanation for how sleep serves a restorative function, in addition to its well-...


8

Studies have proven somewhat the opposite of what you're asking For example a study from 2004 - "The impact of extended sleep on daytime alertness, vigilance, and mood" found that, Average daily POMS vigor and fatigue scores also improved during the sleep extension period And thus concluded Extended sleep leads to substantial improvements in daytime ...


8

The short answer is: Yes. Fatal familial insomnia is a genetically passed down disease that at some random point in a carriers life will suddenly stop them from sleeping, ever, they die within 7 to 18 months I know you did not ask about the disease, but it shows (even without illegal war tests) that it will kill you eventually, even in humans. I believe ...


8

From Poor sleep as a potential causal factor in aggression and violence In most people poor sleep will not evoke actual physical aggression, but certain individuals, such as forensic psychiatric patients, may be particularly vulnerable to the emotional dysregulating effects of sleep disturbances The relation between sleep problems and aggression ...


7

The question piqued my interest, but after hunting through the literature for a bit, I hadn't found any direct answers. Then I went back and read the mouse study you cited a bit more carefully. The mouse study only made a reference to mice being affected at 4 lux, ~100x more sensitive than humans. However, for that number it cited a paper in Science that ...


7

The name used frequently for this phenomenon is "Post-lunch dip". "The post-lunch dip is a real phenomenon that can occur even when the individual has had no lunch and is unaware of the time of day. This dip has its roots in human biology, and may be linked to the size of the 12-hour harmonic in the circadian system. It is certainly exacerbated by a high-...


7

These are called hypnic jerks, also known as hypnagogic jerks or sleep starts. They are normal part of the wake-to-sleep transition. Hypic jerks consist of non-periodic myoclonic movements, generally involving an isolated limb. The exact physiologic origin of hypic jerks is unknown. We can say that they correlate with a particular waveform on the EEG known ...


7

According to Crispim et al 2011, caloric intake late at night is correlated negatively with sleep quality: We conclude that food intake during the nocturnal period is correlated with negative effects on the sleep quality of healthy individuals. Indeed, food intake near the sleeping period (dinner and late night snack) was negatively associated with sleep ...


7

Integrated spindle activity is just this paper's measure of the intensity of spindles. It isn't really a term of art, there is no defined thing "integrated spindle activity," it is just a description for their method of quantifying spindles, or in other words operationalizing their definition of spindle activity. Spindles are brief bouts of (relatively) ...


6

Adenosine causes humans to become sleepy. But how ? During day time we consume food which is broken down into glucose. This glucose is broken down by "Glycolysis" in cell's cytoplasm during which ATP is produced. This produced ATP is is then used by body as an energy supplier. ATP breaks down into ADP and then AMP with the release of energy which our body ...


6

The medical term is "lagophthalmos" if the person is unable to close their eyes at night. There are several factors involved, and unless it's due to physical obstruction, lid archetecture (such as short lid length (due to surgery etc)), or facial nerve (CN VII) problems, it's not well understood. I have seen numerous people with varying degrees of this ...


6

It would be better to say that they go into an inactive, low metabolic state. This low metabolic state is often driven by the temperature in the air itself; ectothermic butterflies require outside heat-energy to become active. Basically they use this time to digest their food and produce sperm/eggs. (reference). At night, or during inclement weather, most ...


6

I did a quick search and found some research in this area. Sleep inertia is the technical term for feeling groggy for a while after waking up. In a review article by Patricia Tassi, Alain Muzet (Sleep inertia. Sleep Medicine Reviews. Volume 4, Issue 4, August 2000, Pages 341–353), they define sleep inertia as Sleep inertia is a transitional state of ...


6

For this answer I assume that we are talking about sleep in healthy individuals as well as fainting as an isolated event without underlying disease or injury. The most common form of what we call "fainting" is vasovagal syncope. It is caused by a drop in blood flow to the brain (cerebral hypoperfusion) e.g. by (false) activation of the parasympathetic ...


6

The brain does not "shut down" during sleep. While not everything about sleeping is understood, we do know that certain areas in the brain remain active during sleep. There is a good overview on sleep on the website of the National Institute of Neurological Disorders and Stroke. Until the 1950s, most people thought of sleep as a passive, dormant part of ...


5

The release of the hormone melatonin is responsible for the feeling of sleepiness. It is released by the pineal gland and production starts when the light fades, as it's production is inhibited by light stimulation of the retina, the onset of the production is called dim-light melatonin onset. Artificial supplementation can increase sleep quality and ...


5

Polyphasic sleep can allow people to sleep at multiple regular intervals throughout the day and allows people to get by with less total sleep. I don't know of any training that can help people reduce the amount of monophasic sleep they need without a negative impact.


5

Have you ever tried to read a complicated book after several hours of hard work that required a high concentration? Imagine that you have forced a particular area of your brain. After a hard work, the areas of the brain that we used to finish a work seem don't respond to any stimulation and make us feeling tired and as we can't understand what we are doing ...


5

Disclaimer: the shortest answer still remains we don't know...yet. Talking from the evolutionary perspective, I have found as many as 8 theories about the purpose of dreaming, some of which even contradict each other(!). But I'll describe them one at a time. One obvious theory is that we dream about something we dream of. So, dream is basically a way of ...


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