Why Do We Sleep? Body and Mind Health

Do all animals sleep?
Why do we sleep?

Is there evidence to answer these questions?

Evidence supports the theory that sleep is a housekeeping function to allow our new memories to be fully processed, while the brain takes a break from new input and prevents buffer overflow issues from occurring. The RAM data needs to get moved to the HDD/SDD, or else we can sort of run out of RAM to process other things in general. Makes sense?

As far as our observations of nature can tell, all animals, human or not, sleep. Even some birds and dolphins whom we thought did not sleep, send half of their brains to sleep at a time.

Why we sleep involves many parts of the body. A "drainage system" exists where the lymph nodes drain waste from tissues in the body, and increases activity when we sleep. Sleep helps to clean up the body.

The reason for all animals sleeping, however, may be elusive to know.

Rats can die without sleep for a month, and humans can hallucinate or go into seizures after a few days.

Sleep helps us retain memories from learning, as testing has shown. But the memory storing process that takes place during sleep is unclear.

One theory is that the active neuronal connections of memories can be chopped down in accuracy or vividness to make room for new memories the next day. To learn, sleep seems to be required.

New evidence supports this. 12 mice has their synapses measured. After sleeping, they shrink by 18 percent compared to those before sleep. Sleep weakens the connection between neurons.

With these recent findings, it can make more sense why we have more trouble thinking, concentrating and learning if we miss a night's sleep. The connections are still full of info and haven't been reduced to allow them to encode new information. Sleeping well before, and after, learning something, is the best.

Interrupted sleep is also an issue. Deep, slow-wave sleep is best for shrinking the synapses and restoring our capacity. We might think that sleep weakens the brains connections, and that this explanation is counter-intuitive. But EEG recordings previously supported such an idea because waking up from sleep shows electrical responsiveness at the start of the day compared to the end.

However, this new evidence is more concrete. It took seven researchers 4 years, with 7000 synapses tested in a blind study. In the end, their theory was supported by the evidence.

While there is a thinning of size in some areas, other synaptic connections remain protected. The idea is that this is where the most important memories are stored. We whittle down the short term memories of the day, keep some as more vivid, while others much less so. The detail and accuracy varies, and we get to recall them. Maybe all memories of the day are simply shifted onto a separate array in brain matrix to later lose resolution of quality. This way our active neuronal connections can be free to learn more new information and keep on going.

Sleep is very important for our overall health, in both body and mind. Getting enough sleep throughout your life is required. You can't just catch up later in your older age, as that's not how it works, as also in older age the quality of sleep is also reduced making getting quality sleep that much harder.