3 ms·

How much of sleeping is explained by metabolism reduction/calorie conservation?

eigenspace 8y ago
In humans, metabolism only goes down ~35% at its very lowest point during deep sleep. In other phases of sleep, your metabolism is ~15% lower than during waking time. If sleep were for metabolic savings, it would be an incredibly inefficient way to go about it. In some senses, wakefulness may be thought of as neurotoxic and much of whats going on during sleep is centred around repairing the damage caused by being awake. For instance, the glial cells between your brain neurons shrink allowing your body to flush the beta amyloid from your brain with cerebral fluid. Beta-amyloid is a neurotoxic protein which causes Alzheimer's an is a byproduct of waking brain function. This explains the link between Alzheimer's and sleep deprivation. Sleep is also the phase where short-term memories are evaluated and either discarded or integrated into long-term memory. It's also essential for your immune health and cancer prevention. Your body produces dozens of cancer cells daily, but they're killed by your immune system. After only a single night's sleep deprivation, your amount of cancer-killing immune cells plummets. This is why shift work is now classified as carcinogenic in several countries. ____________________ Edit: Just on the topic of sleep being for energy savings, did you know that during hibernation (a state actually used for energy savings), bears will actually leave their hibernating state in order to sleep? I think that fact really showcases how important sleep is and should put to rest any notion that sleep is for energy savings.
- jacobolus 8y ago
  Sleep deprivation doesn’t just affect cancer. With immune suppression chronic viral infections like warts flare up after a day or two of sleep deprivation. Allergies get worse. Anxiety shows up more easily (in response to milder stressful stimuli), has stronger effects, and takes longer to subside. In general cognitive function is impaired: alertness, memory, attention span, ... The skin and hair get greasier. ...
  - eigenspace 8y ago
    It is amazing how long one can go on listing new, exciting ways one's body begins to fail when sleep deprived.
ravar 8y ago
Probably none considering that calories are collected while awake, and there exist animals that collect calories during the night and the day.
- hexane360 8y ago
  I agree with your conclusion, but this isn't sound logic. This assumes food is never supply-limited. If it is, then it could be advantageous to lie dormant for a period to allow supply to regenerate. Imagine a farmer who plants food (ideally low maintenance food) and then hibernates until it is fully grown.
  - jacobolus 8y ago
    Something like human hibernation is reportedly possible for people who live isolated lives in places with tough winters (can’t remember where the article I read about this a few years ago was). It doesn’t happen in the modern world though: abundant food, many distractions, artificial lighting, climate controlled spaces, ...

In humans, metabolism only goes down ~35% at its very lowest point during deep sleep. In other phases of sleep, your metabolism is ~15% lower than during waking time. If sleep were for metabolic savings, it would be an incredibly inefficient way to go about it. In some senses, wakefulness may be thought of as neurotoxic and much of whats going on during sleep is centred around repairing the damage caused by being awake. For instance, the glial cells between your brain neurons shrink allowing your body to flush the beta amyloid from your brain with cerebral fluid. Beta-amyloid is a neurotoxic protein which causes Alzheimer's an is a byproduct of waking brain function. This explains the link between Alzheimer's and sleep deprivation. Sleep is also the phase where short-term memories are evaluated and either discarded or integrated into long-term memory. It's also essential for your immune health and cancer prevention. Your body produces dozens of cancer cells daily, but they're killed by your immune system. After only a single night's sleep deprivation, your amount of cancer-killing immune cells plummets. This is why shift work is now classified as carcinogenic in several countries. ____________________ Edit: Just on the topic of sleep being for energy savings, did you know that during hibernation (a state actually used for energy savings), bears will actually leave their hibernating state in order to sleep? I think that fact really showcases how important sleep is and should put to rest any notion that sleep is for energy savings.

jacobolus 8y ago
Sleep deprivation doesn’t just affect cancer. With immune suppression chronic viral infections like warts flare up after a day or two of sleep deprivation. Allergies get worse. Anxiety shows up more easily (in response to milder stressful stimuli), has stronger effects, and takes longer to subside. In general cognitive function is impaired: alertness, memory, attention span, ... The skin and hair get greasier. ...
- eigenspace 8y ago
  It is amazing how long one can go on listing new, exciting ways one's body begins to fail when sleep deprived.

ravar 8y ago

Probably none considering that calories are collected while awake, and there exist animals that collect calories during the night and the day.

hexane360 8y ago
I agree with your conclusion, but this isn't sound logic. This assumes food is never supply-limited. If it is, then it could be advantageous to lie dormant for a period to allow supply to regenerate. Imagine a farmer who plants food (ideally low maintenance food) and then hibernates until it is fully grown.
- jacobolus 8y ago
  Something like human hibernation is reportedly possible for people who live isolated lives in places with tough winters (can’t remember where the article I read about this a few years ago was). It doesn’t happen in the modern world though: abundant food, many distractions, artificial lighting, climate controlled spaces, ...