Hot answers tagged sleep
19
This good non-scholarly article covers some of the usual advantages (rest/regeneration).
One of the research papers they mentioned (they linked to press release) was Conservation of Sleep: Insights from Non-Mammalian Model Systems by John E. Zimmerman, Ph.D.; Trends Neurosci. 2008 July; 31(7): 371–376. Published online 2008 June 5. doi: ...
9
I found this paper by Benington and Heller that expands on the previously mentioned theory of sleep as a mechanism to renew metabolism. They hypothesise that sleep is necessary to replenish glycogen stores (mainly within astrocytes) in the brain. These stores are normally used to supplement blood glucose due to the high energy demands of the brain.
It ...
6
From what I've learned, there are two theories to answer that question:
Restoration - the body needs to rest in order to renew its metabolism (if an animal is active 24/7, it will constantly use up a lot energy and metabolism). It has been shown that mice that have gone a while without sleeping have a compromised immune system.
Preservation - sleep is ...
5
Reading "Polyphasic Sleep: Facts and Myths (Dr Piotr Wozniak)", it is pointed out that infant humans do undergo polyphasic sleep. As this is where most of our development is obviously done, I do not know where I can further proceed with the question about how it would affect development? Perhaps the issue is more how it would effect the day to day ...
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
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 ...
5
There's an excellent, comprehensive review article on the entire process of REM sleep:
Vetrivelan,R, Chang, C, Lu,J (2011). Muscle tone regulation during REM sleep:
neural circuitry and clinical significance. Archives Italiennes de Biologie, 149 [DOI] [Free PDF]
Projections from the sublaterodorsal nucleus (SLD) of the Pons in the brainstem are ...
4
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 ...
4
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 ...
4
On the analytics of melatonin I have here a german language text by the RKI with references. Translated quote:
Assay of melatonin is done by serum or sputum using RIA or ELISA.
Alternatively, to infer the nightly amount of melatonin secretion it
is possible to look for the melatonin catabolic metabolite 6-hydroxy
melatonin sulfate (6-OHMS) in ...
3
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 ...
3
I'm not aware of any study testing this hypothesis. I would surmise that adverse health effects are likely because the circadian clock operates on a 24-hour time frame, and because lack of sleep for ~40 hours every second day will alter hormone, cytokine and other measures to levels not normally seen in 8-hour sleep/16-hour wake cycle.
3
Human sleep cycles and dream times, what influences the timing and intensity? Sleep history included
I'm interested in learning what influences the desire to go to bed at
a particular time? What influences the getting out of bed times?
It is the circadian rhythm. Circadian rhythm is mediated by the suprachiasmatic nucleus of hypothalamus, which gets afferent nerves from optic nerve. So, the circadian rhythm is mediated by light. Initiation of the ...
2
(too long to be a comment)
You may be interested in http://en.wikipedia.org/wiki/Phase_response_curve.
This graph shows how the body's circadian rhythm normally works: http://en.wikipedia.org/wiki/File:Body_Temp_Variation.png. Body temperature decreases during the night (apparently due to more melatonin production.
I conjecture that the proposed schedule ...
2
Puffy eyes are caused by fluid build up in tear ducts from extended periods of lying down. Gravity from sitting or standing slowly drains them during the day. The crusty 'sleep' that accumulates in the corner of your eyes is the residue from basal tear liquid that has seeped out of the eye and evaporated during the night.
2
Sleep is not homogenous - there are different phases of sleep - REM, NREM-1 to NREM-4. And these different stages may play different roles in 'rejuvenating' the body (as you put it).
When you first fall asleep, you go into NREM-1 phase, which is the lightest sleep, and progresses into NREM-4, and for the first half of your sleep cycle, this cycles so you go ...
2
I'd say that unihemispheric sleep and adaptations like it really are sleep - the brain activity on one side of the brain gives a characteristic sleep pattern. It certainly must satisfy the needs of an aquatic mammal like a dolphin or a whale since they have to be partially conscious to breathe by surfacing regularly.
It does seem to affect the brain ...
2
I found a recent PLoS article that said that none of hypochondriasis, depression, hysteria, psychopathic deviate, masculinity-femininity, psychasthenia, schizophrenia, or social intraversion (on the MMPI-2) "were associated with any melatonin parameter."
However, it does appear that "increases scores of Hypomania and Paranoia were associated with a shorter ...
2
Found a few samples here: http://ars.els-cdn.com/content/image/1-s2.0-S0024320503008142-gr2.gif this shows the nocturnal melatonin peak, which is apparently very important for well being
1
From Kalsbeek et al 1999 Neuroscience (link 1, link 2)
"retina-mediated photic activation of suprachiasmatic nucleus neurons
induces the release of GABA from efferent suprachiasmatic nucleus
nerve terminals, resulting in an inhibition of melatonin release by
the pineal gland."
So it appears that GABA is key. When the retina is stimulated by light ...
1
Take a look at this (especially page 938): Coordination of circadian timing in mammals by Steven M. Reppert & David R. Weaver Nature 418, 935-941 (29 August 2002) | doi:10.1038/nature00965
Sodium-dependent action potentials provide the primary means by which
the SCN transmit circadian outputs to other brain areas and are
essential to its role as ...
1
There are many signalling molecules used by the human body that have a different effect depending on the cell type. My guess is that serotonin causes these different effects in different neurons. So, while serotonin is capable of promoting feelings of arousal and sleepiness, the two do not necessarily go together. If you look into this more deeply you will ...
1
I haven't heard of studies like the one you're proposing, but you can test this hypothesis on yourself with this app.
Knowing you need to sleep less than your usual amount will probably affect the quantity and quality of your sleep, but not because of an "internal clock". Most likely, whatever you need to wake up early for will cause you some anxiety, ...
1
I thought this was an interesting subject and I had some time to do a little search around today. I can't find anything better than the review you point out. All I can do is add a few interesting notes since 2001. Nothing really turns over Rattenborg et al.
Sleep is itself a poorly understood process and most of the theories of the necessity of sleep can ...
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