Case against Sleep
From an evolutionary perspective, sleep makes no sense; it is utterly idiotic.
Before the 1950s, most people believed sleep was a passive activity during which the body and brain were dormant. But it turns out that sleep is a period during which the brain is engaged in many activities necessary to live — which are closely linked to the quality of life.
Why did evolution strongly select sleep?
The reason elders wake up at dawn and teenagers stay awake into the late hours might be related to how our ancestors in ancient times guarded their settlements.
The variation in circadian rhythm in humans has developed as an evolutionary response for survival & reproduction. However, when we are asleep, we are neither reproducing, hunting, working, nor taking care of others. For tribes, this vulnerable time could lead to predator attack. This presents a compelling argument against sleep. However, sleep is considered crucial at the most fundamental biological level, making it hard to comprehend nature’s favoritism towards sleep.
Frederick Snyder presented a premise: ‘Man and other animals have learned that under conditions of danger, it is safe to sleep only if sentinels are employed to remain vigilant.”
There is a wide range of sleeping patterns that would have been advantageous for ancient humans from an evolutionary standpoint, ensuring that at any given time, at least one individual would remain alert to protect the tribe in case of danger.
Sleep patterns are typically distributed, with approximately 30% of people at the spectrum’s extremes and about 70% concentrated in the middle. Electricity and other modern amenities have pulled the two worlds apart. Now, a bell-curve distribution with nearly 12 hours separates the extreme morning people from the extreme night people but most people fall in the middle.
Sleep is essential for survival, yet it also represents a time of extreme vulnerability to predation, hostile conspecifics and environmental dangers. To reduce the risks of sleeping, the sentinel hypothesis proposes that group-living animals share the task of vigilance during sleep, with some individuals sleeping while others are awake.
Anthropologists studied the Hadza, hunter-gatherers who live in modern-day Tanzania and found that at least one person was awake 99.8% of the time.
Bear: sleep and wake cycle coincides with the sun
Lion: early to bed and early to rise
Wolf: prefers sleeping in late and going to bed late
Dolphin: no set sleep schedule
Night Owls
There is no universally accepted theory of why some people are night owls. However, evolutionary biologists believe societies with more chronotype variation may have been more likely to survive. In addition, people called night owls or categorised as an “eveningness” type may find incorporating activity into their day more challenging. Finally, for many night owls, careers or other demands on time may mean a morning alarm rings well before their natural wake time.
As a result, a night owl or eveningness type may start the day relatively “jet-lagged” — feeling out of sync with their body due to being awake when the body would prefer to be asleep.
They also may be sleep deprived if they have to get up significantly earlier than desired. As a result, they may contribute to less activity regularly.
Circadian rhythms of night owls are out of sync with the world as we have shaped them, but it does not mean that they are lazy. Instead, there is a socially ascribed miscalculation of how we should function in time as a society.
The notion that ‘night owls or wolf chronotypes’ are compromised earlier in the day supports the concept of adaptive schedules to level up their productivity. In addition, it allows for the disadvantage created when tasks are set early morning for a late-night chronotype.
What happens when we sleep?
We know that sleep regulates our blood sugar levels, controls our appetite, regulates sex hormones, fixes memory, and we learn and remember during sleep. In addition, it reduces the emotional difficulty and sweeps away the toxic proteins that build up in the brain.
Sleep drive also plays a key role: Your body craves sleep, much like it hungers for food. Throughout the day, your desire for sleep builds, and when it reaches a certain point, you need to sleep. A major difference between sleep and hunger: Your body can’t force you to eat when you’re hungry, but when you’re tired, it can put you to sleep, even if you’re in a meeting or behind the wheel of a car.
When you’re exhausted, your body is even able to engage in microsleep episodes of one or two seconds while your eyes are open. Napping for more than 30 minutes later in the day can throw off your night’s sleep by decreasing your body’s sleep drive.
At one point in human history, the sleep timing of morning larks and night owls was probably only a few hours apart, he says.
In the modern world, unlike the tribes, we can rest at different times. This aspect nests very insightful questions: just like animals, can we sleep with one-half of our brain and the other half wide awake now?
Unihemispheric slow-wave sleep (USWS) is when one half of the brain rests while the other half remains alert. Unfortunately, there are only a few species that can do this.
So, for example, when dolphins sleep, half of their brain will be fast asleep. The reason is that they need to maintain aquatic mobility they need to keep. Otherwise, that’s going to be a good outcome.
We also know that many bird species will have such sleep structures. Now think about what happens if all the flock of birds land on a branch simultaneously to rest.
Here’s the question for humans: do you get to sleep with both halves of the brain asleep or just one half?
The complexity of brain wiring in humans and sleep architecture is challenging for one-half of the brain to remain awake, suggesting that if sleep were dispensable, nature would have found a different way for us to get all its benefits.
We are a tribe species now. Circadian rhythms are a 24-hour, cyclically driven biological sequence. Evolutionarily, humans developed variations in circadian rhythms, that is, morningness and eveningness chronotypes, for survival and reproduction.
Being an early bird, or the opposite night owl, is usually not considered highly under our control. This is because some people are genetically hardwired to sleep early, while others get a second wind and tend to sleep late.
Specifically to facilitate short-term mating and to ensure the most extended protection period over 24 hours.
We have our sleep chronotype, which means many of us are a morning type, evening type or somewhere in-between. The person doesn’t get to decide; it’s not one’s choice.
Let’s see why brain wire is split across our prototypes.
If you are in a tribe where we all sleep simultaneously, suppose there are thunderstorms for 8 hours. This genetic technicality of when people desire to sleep would protect your people. Because the entire tribe depends upon sleep as the nucleus of this group of Homo sapiens, everyone gets hours of sleep, and the whole tribe’s core of this group is only interchangeable.
A clever solution that nature has come up with is that everyone gets there 8 hours but, as a species, only going to be available for 2 to 3 hours at max. So, everyone at least has a collective sleep; absolute genius!
You can’t get away from sleep. You have to sleep. It’s evolutionary.
Put another way, the period of highest risk from predators is when the village sleeps.
We have a good reason for night owls, morning larks, and everyone in between to exist. These variations are equally necessary as a biological clock of one is merely set to an earlier hour than the other.
