Hot answers tagged sleep
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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.
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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 ...
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 ...
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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 ...
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 ...
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 ...
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(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
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
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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 ...
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 ...
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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, ...
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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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