Probably not. If a lot of energy is being used in the clean up process, then the need for sleep is most likely driven by the physical advantages of sleep, not the advantage of using less energy or similar.
Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more fluid to be pumped in and wash the toxins away."
Neurons are powerful cells that are so active that they cannot even keep themselves healthy. The glial cells are there to help. If the glial cells are shrinking and (presumably) partially shutting down in order to efficiently clean out the brain, then sleep is an efficient engineering solution -- you are trading off having a super-active brain for ~16 hours at the cost of a less effective brain for ~8 hours.
There may be less efficient solutions that allow for 24 hours semi-wakefulness, we might be able to tune the total activity of the brain down for continuous operation, but being in a groggy half-asleep state all day is probably not what you were hoping for.
It's an interesting choice from an evolutionary standpoint: At the time homo sapiens evolved, we presumably had saber-tooth tigers, tyrannosaurus rexes, abonimable snowmen (or whatever :) prowling the bushes around the place we slept.
If you were all alone, wouldn't it be a better survival trait to be groggy 24h/day than to be fully alert 16h/day and dead to the world the remaining 8h?
I've heard that there are species of fish (and possibly birds) that are awake around the clock; they deal by sleeping one brain hemisphere at a time, which leaves enough active brain to avoid obstacles and predators.
If humans never took that evolutionary road, does it mean that we are genetically disposed to social groups, i.e. "someone else is watching your back while you sleep"?
> I've heard that there are species of fish (and possibly birds) that are awake around the clock; they deal by sleeping one brain hemisphere at a time, which leaves enough active brain to avoid obstacles and predators.
Whales are known to do this; I imagine it makes breathing much less difficult.
Note this quote: "Cells in the brain, probably the glial cells which keep nerve cells alive, shrink during sleep. This increases the size of the interstitial space, the gaps between brain tissue, allowing more fluid to be pumped in and wash the toxins away."
Neurons are powerful cells that are so active that they cannot even keep themselves healthy. The glial cells are there to help. If the glial cells are shrinking and (presumably) partially shutting down in order to efficiently clean out the brain, then sleep is an efficient engineering solution -- you are trading off having a super-active brain for ~16 hours at the cost of a less effective brain for ~8 hours.
There may be less efficient solutions that allow for 24 hours semi-wakefulness, we might be able to tune the total activity of the brain down for continuous operation, but being in a groggy half-asleep state all day is probably not what you were hoping for.