According to dungeons and dragons, Elves don't sleep, but go through a process called reverie. This is a meditative state in which they retain the restorative of sleeping, but they remain fully conscious throughout it. It is similar to REM state, where breathing and brainwaves slow down, and muscles relax. Elves are fully aware in this trancelike state, and must remain here for 4 hours. Not taking Revere for long periods of time will increase their disorientation and eventually send them into a coma.

I want to give the humans of my world this ability while making them incapable of sleep. What brain or biological mechanism is needed to make this feasible ?


It is believed that meditation can be used to offset sleep in humans. The exchange ratio varies (30 minutes of meditation to replace 1 hour sleep is a common claim), so we're already on that way.

The two parts of the brain I would focus on are the Ascending reticular activation system (ARAS) and the Ventrolateral preoptic nucleus (VLPO). The VLPO is responsible for managing the antagonistic relationship between neurons that encourage sleeping and neurons that encourage wakefulness, and the ARAS is responsible for actually carrying out the changes between waking and sleeping. Altering either of them has drastic effects on sleep. It would probably be "easier" to make the changes to VLPO to simply no longer have neurons that encourage sleeping.

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    $\begingroup$ I think you're quoting a very contentious claim from somewhere. Would you please quote the source of the research relating to replacing sleep (particularly deep sleep) with meditation. $\endgroup$ – StephenG Jun 7 '18 at 1:37
  • $\begingroup$ @StephenG I phrased it as "It is believed.." because there is contention. However, there does seem to be a lot of evidence pointing in that direction. Here is an article which sites several sources, including a study done in 2010 by the University of Kentucky. $\endgroup$ – Cort Ammon Jun 7 '18 at 2:15
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    $\begingroup$ "It is believed" is ambiguous and I'd suggest "It has been suggested" is more what you are aiming at. The first link suggests that total sleep time of (average) 7.8 hrs was replaced by total sleep+meditation time of 5.2+2.3 hrs = 7.5 hrs. That doesn't sound like much of a difference to me and could be within statistical error as well. $\endgroup$ – StephenG Jun 7 '18 at 2:26
  • $\begingroup$ @StephenG I was focusing on the ability to replace sleep with meditation. You're right, that if the goal is to replace 8 hours of sleep with 4 hours of meditation like the elves do, the research suggests it wont work. But if your goal is to replace 8 hours of sleep with 8 hours of meditation, it'd work. $\endgroup$ – Cort Ammon Jun 7 '18 at 2:29
  • $\begingroup$ This is coming from the same new age groups who promote breatharianism to overcome the human need for food, or the lady at my work who thinks she can manipulate energy auras to cure cancer. I would do some pretty in depth research before I bought into that claim regarding sleep being replaced by meditation. Its probably just napping sitting up or something at best. At worst its probably some guy trying to sell you his glorified workout and diet DVDs. $\endgroup$ – TCAT117 Jun 7 '18 at 3:24

Here's how brain waves differ;

  1. Gamma State: (30 — 100Hz) This is the state of being hyperactive and actively learning. Gamma state is the best time to try and retain information. however too much of this will lead to anxiety and stress.

  2. Beta State: (13 — 30Hz) our most common waking state, Beta State is associated with the alert mind state of the prefrontal cortex. This is a state of the “working” or "thinking mind"

  3. Alpha State: (9 — 13Hz) We feel more calm and relaxed while in the “alpha state” after a yoga class, a walk etc. We are lucid, reflective, have a slightly diffused awareness. The hemispheres of the brain are more balanced (neural integration)

  4. Theta State: (4 — 8Hz)this is the state where we can meditate at . it is categorised by the ability to visualise.It is also makes one feel somewhat drwosy with a higher capacity for intuition and problem solving.

    5.Delta State: (1—3 Hz) Tibetan monks who have been meditating for decades can reach this in an alert, wakened phase. It is the same type of brain activity we all experience in dreams but they can do it while awake.

So yes it is possible after much , much practice. some things that slightly less practice include things such as lucid dreaming. There was once a famous european violinist ( although his name escapes me) who they say used to practice in his dreams. Not to mention the great Indian mathematician Ramanujan who attributed most of his ( absolutely amazing!) work to his family goddess who he says came to him in his dreams and showed equations to him , often waking up with some radical idea that he would never bother to prove but that would be proven by others to be correct. So this too could be useful to you if the reason you want them to stay up is motivated by economy or desire to practice etc .


They are doing what dolphins do, sleeping one half of their brain at a time. dolphins who have to swim and breath of course cannot sleep the way we do, they will drown. Instead they sleep only one half of their brain at a time, maintaining low activity awareness the whole time. The process even takes 4 hours (2hrs per side) in dolphins. they are alert enough to spot predators, but they can't do much besides swim slowly, breath, and see until they wake up.

Missing it too often is just like missing sleep for humans. Severe sleep deprivation in a normal humans leads to hallucination, coma, and death.


Nothing can substitute for sleep because sleep is not just resting. It's a physical state in which life-critical biological housekeeping gets done. The human body can't clean and repair its brain while the brain is in operating in conscious mode. If you want to make your humans do without sleep, then you just need to make up a reason, like they meditate and reconnect with the spirits of the ancestors, who then magically rejuvenate them or something. Or, you can just say they meditate, and your reader will probably forgive you if the story is a good read.

Humans can't retain the benefits of sleep through meditation, because a critical function of sleep is to remove metabolic toxins from the brain. Meditation doesn't do that. The buildup of the metabolic toxins causes some of the effects of sleep deprivation and if enough toxins accumulate, they cause neuron damage and cell death.

"The brain only has limited energy at its disposal and it appears that it must choose between two different functional states — awake and aware or asleep and cleaning up. You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can't really do both at the same time." Source Source

The brain also assists the body with healing during sleep by releasing hormones that promote healing, among other things. Lack of sleep has a host of bad health effects which would probably lead to an early death.

"The physical healing of wounds is expedited by sleep, and sleep strengthens the immune system in general. Rats deprived of sleep in experiments show distinctly inferior healing capacities, develop skin lesions, lose body mass, and are unable to maintain a stable body temperature, ultimately dying of sepsis or just “exhaustion”. Sleep-deprived rats have been shown to exhibit substantially fewer leukocytes (white blood cells), the body’s main defence against infection, and sleep-deprived humans show less than half of the protective antibodies after an inoculation jab as compared to people with healthy sleep patterns." Source Source

If you want to know more, just do an internet search for the terms sleep brain metabolic clean and sleep allow body heal.


The idea of elf's daydreaming instead of sleeping comes from Tolkien originally. I would propose that this is not likely to be done on a the long term unless these humanoids have a great amount of neurons to sacrifice or a different regeneration method for neurons (wich in humans occurs rarely).

Following that, if they had two minds associated with two different brains they could sleep and renew one while being conscious with another. The other brain could work as a hive mind so not to create a dissociative disorder in the person. The hive mind wouldn't be connected to any senses so it can go to sleep at a different time while the individual brain is awake.


One of the items you want to incorporate is the release of Human Growth Hormone.

HGH is essential to making people thrive. The myth is it's only good for making children taller. The reality is that every one, of every age, needs it. It's how we rebuild muscle fibers after breaking them down through activity during the day. HGH also regulates insulin, breaks down toxins in the body, helps produce substances such as breastmilk, and does all sorts of other things.

It is only released during sleep. If you've read about weight lifting how it's not the workout that builds your muscles, it's sleeping on it, this is why. Without HGH your muscles will slowly get weaker and you will have a lot more soft tissue pain (fibromyalgia, etc). Other body systems will start to break down. It won't kill you (not directly anyway) but it can really alter your functioning.

A normal person can miss sleep now and then and be fine. But if you miss sleep for weeks or months, the HGH loss alone will really have an effect.


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