3
votes
1answer
53 views

Does tea have its effect if you have a sleep after drinking it?

If I drink tea, then go to sleep for a while, when I wake up, will the effect of tea still be on me (the refreshing effect)? Does it depend on the duration of sleep?
5
votes
1answer
92 views

Which part of human eyes is getting tired?

It's a thing of common sense that if you read, drive or look at computer screen for too long your eyes will get tired. They burn, itch and try to close all the time. But I was wondering which part(s) ...
6
votes
2answers
128 views

How would the human body adjust to sleep times if we were to live in a place with different day lengths?

You sleep at night and are active during the day that's how things work for humans, but theoretically if a human whose parents lived on earth were to be born in another planet resembling earth but the ...
0
votes
0answers
32 views

Emissions sunrise, sunset linked to human productivity (awakeness)?

I do want to find a solution to a (for me) confusing state of mind. I'm a bit of a night-owl, always been one. The whole day I prolongue work that I want to do, my brain seems to sleep-in until after ...
5
votes
1answer
134 views

What causes Paresthesia (Pins and Needles) at a cellular level?

I've looked it up in plenty of places like the Wikipedia page and such, and it is clear that the most common cause of Paresthesia is either a fair amount of pressure on a specific patch of skin ...
2
votes
4answers
148 views

Why do the humans become sleepy after meals?

I don't know about all the mankind, but I know enough people, who becomes sleepy after their meals. Also, I'm not sure, what kind of food do they consume, but I personally get sleepy almost from any ...
4
votes
1answer
88 views

Does playing music during sleep actually suppress rather than rouse the brain?

I've long been interested in the effect of music/sound on dreaming, and even built 2 apps that play music during REM period. Now I'm looking at this article about FMRI studies of a sleeping brain, and ...
1
vote
0answers
22 views

Is there a homeostatic setpoint for number of hours of sleep required by a human?

I've heard this TED.com talk about dieting and it mentions that there's a very definitive setpoint within the human brain about how much a human should weight. The speaker mentions that after as much ...
6
votes
1answer
283 views

Why do people sleep with their eyes open?

It's a fact that some people sleep with their eyes open, but why does that happen? Is it normal behavior, not a symptom of any sort of disorder? Are there any (dis)advantages to sleeping with eyes ...
6
votes
2answers
220 views

Is there a preferred sleeping position for humans?

I remember hearing various sleep related advice as a child, like "sleep on your right side", or " have your head pointed in X direction". Is there any biological reason why sleeping on one side ...
3
votes
1answer
1k views

Why do you need you room dark for melatonin release?

There is a light pollution movement that says lighting at night obstructs melatonin production. They say: What makes you fall asleep are changes in the level of the hormone melatonin ...
13
votes
2answers
249 views

Can parts of a human brain be asleep independently of each other, or vary in the times required for them to fall asleep?

I know that some birds and marine animals can continue complicated activity (swimming, flying?) while one hemisphere of their brain is asleep. I'm interested if human brain has some parts of it that ...
9
votes
3answers
525 views

How are our senses dimmed during sleep?

Our senses are not as sensitive during sleep compared to wake. There is an arousal threshold during sleep that only when it is overcome will it wake a person up. My question is how is this arousal ...
2
votes
2answers
222 views

What mechanism suppresses melatonin release in humans?

I'm looking at melanopsin, a photo pigment in the human eye. One of its actions is to trigger suprachiasmatic nuclei SCN to suppress melatonin release. I'm interested in learning what is the exact ...
2
votes
1answer
60 views

Are (baseline) high blood levels of melatonin associated with either circadian rhythm or mood disorders?

(Exogenous) melatonin is administered at night for treatment of circadian rhythm disorders, but melatonin taken during the day is linked with depression. I would like to know if high blood levels of ...
3
votes
1answer
216 views

The fundamental importance of R.E.M. Sleep. (Rapid Eye Movement)

Question: I know that experiments have been conducted to determine the importance of R.E.M. sleep in our sleep cycle. It is particularly important for learning, information synthesis, and recovery ...
6
votes
1answer
187 views

Is there a normal human melatonin concentration to light level curve?

I'm looking for a graph or a curve that would show the typical concentration of melatonin in blood or saliva for humans over 24 hours. It would be good to know the photoperiod for the same human as ...
13
votes
1answer
458 views

What light intensity starts melatonin release in humans?

I'm interested in whether any studies have determined the intensity of light at eye level that starts melatonin release in humans. I know that: melatonin release is suppressed by blue light with ...
1
vote
0answers
50 views

Does Dorsal Raphe Nuclei firing pattern change in response to voluntary breathing?

I'm reading this paper, which discusses how Serotonin may be involved in motor functions of mammals: 5-HT and motor control: a hypothesis . The paper includes the following diagram of the Dorsal ...
10
votes
1answer
133 views

Does sleep in humans re-structure based on the expected sleep time?

I've read about anecdotal evidence that human brain has a fairly good internal clock that can be used to judge the amount of time that has passed. I'm wandering if there are any mechanisms in the ...
1
vote
0answers
37 views

Can we make any judgements about sleep or readiness to sleep from a heart rate metric and/or pulse oxymetry?

I'm looking at inexpensive and un-intrusive ways to quantify the state of human body/mind . One of these is Actigraphy, which is a study of human motion over time. This can be done with an iPhone ...
2
votes
0answers
244 views

Can the sleep/wake cycle be influenced by non-visible spectrum electro-magnetic radiation?

I've been reading a few papers on Melanopsin and Suprachiasmatic Nucleus (SCN), and see that the sleep/wake transition is ...
3
votes
1answer
236 views

How are melatonin levels measured in humans?

I'm wondering how it is possible to measure diurnal variations of melatonin levels in humans. I keep reading that there should be a large difference in amplitude between melatonin levels measured at ...
3
votes
0answers
99 views

What controls the feeling of discomfort/comfort before and after sleep?

I'm interested in which biological systems or hormones are involved in the following phenomenon: Before sleep it may be difficult to find a comfortable position, and muscular aches and pains are more ...
3
votes
0answers
224 views

What is the timing of information assimilation within a human brain? [closed]

A little background: I'm an avid dreamer and have great dream recall, sometimes up to 5-7 per night. In my experience, I can sometimes trace some elements of the dream to an event that occured ...
4
votes
1answer
225 views

Can humans shorten their sleeping patterns?

Can sleeping patterns be trained, or are they genetic? I read that a human needs to sleep at least 4 hours. Can sleeping time be reduced without having a negative impact?
4
votes
1answer
266 views

Human sleep cycles and dream times, what influences the timing and intensity? Sleep history included

I'm doing sleep and dreams research and have developed an iPhone application to help me track my bedtime, rise time, sleep onset and also mark dreams. The app also monitors overall activity overnight ...
7
votes
1answer
470 views

Why do people look different after a long sleep?

What happens during a long sleep that makes people look odd when they have just woken up? Why doesn't the same phenomenon occur in the case of a person who lies down for an extended period of time, ...
14
votes
2answers
1k views

What causes REM atonia to be lost in sleepwalking?

I understand that in normal REM sleep the voluntary muscles are in effect paralysed in order to prevent an individual acting out their dreams. This paper indicates that there are likley to be ...
8
votes
1answer
2k views

Effects of Polyphasic vs Monophasic sleep in humans

Why do humans practice monophasic sleep cycles? When altering one's circadian rhythm to a Polyphasic sleep schedule, how much would that affect development? Is Monophasic sleep (once per day) ...