Something about Sleep🌙

Do we need sleep? How much sleep do we need? Why do some people need 8 hours of sleep, while others function perfectly on only 6?

Most people of today's world sleep in a so-called monophasic sleep pattern:  long, continuous, and uninterrupted sleep (usually 6-8 hours) during the night. While this sleep pattern is widely accepted as the norm, there are many historical instances where people have accepted other sleep regimens. Monophasic sleep, as we know, for now, proves to be an effective way to a good night’s rest and regeneration of many of your bodily functions. That is, if we take into account that you should have at least 7 hours of good quality sleep at night.

Unfortunately, many of us fail in this task, and as a result, miss the arguably most crucial gift evolution gave us.

The epidemic of sleep loss is seen now more than ever before, and its consequences are easily observed throughout the Western world.

It is important to note that human beings are the only living species that willingly deny themselves a full night of sleep to study, work, or achieve more.

While the psychological motivation to avoid sleep is prevalent throughout modern cultures, there is also a biological reason that many of us cannot achieve 8 hours of quality sleep.

In his book "Why We Sleep", Matthew Walker presents us with the most intricate biological differences that obstruct the way to a night’s rest. The terms "Night owl" and "Morning lark" are not just epithets that describe someone’s preference for being active during the day. The terms are factually true since some people are biologically wired to be most active in the early morning and some at late night. You might be asking why evolution made us unsynchronized in our need for sleep. One theory explains that the most important factor is the number of hours we were left vulnerable, which was incredibly important in the early days of humanity.

When you are firmly asleep, you cannot gather food, form social bonds, or procreate, but are also very vulnerable to every lurking predator. Evolution took care of that by reducing the number of those "vulnerable hours" by inducing a late sleep onset in some and an early sleep onset in others.

For example, Morning larks went to sleep at about 10 pm and woke at about 6 am, while night owls stayed awake till 2 am and were awake at about 10 am. This way, evolution reduced the vulnerable hours to only 4 hours a night instead of 8 hours if we had a synchronized sleeping schedule. So maybe the troubles we have with falling asleep stem from these biological differences.

There is a method to transform yourself from a night owl to a morning lark, but I want to mention one more deep biological difference in our sleeping schedule. It is proposed that monophasic sleep is unnatural to a degree and that it developed during the Industrial Revolution as a means to fit the working schedule. The first proof that supports this fact is seen in many medical texts, anthropological records, and preindustrial textbooks mentioning “first” and “second sleep”.

People slept in a biphasic manner, falling asleep for a couple of hours, waking up for a few hours, and then falling asleep again and remaining asleep until dawn. In those hours between two sleep periods, people would go about their daily duties such as reading, writing, tending to children, or making love to their loved ones. The second proof of our segmented sleep pattern is seen in some cultures that still follow this two-part sleep.

For example, some Mediterranean cultures have a sleep pattern based on siestas, which is about 5 hours of uninterrupted sleep during the night with 2 to 3 hours of naptime or siesta in the early afternoon. 

The third proof of our innate need for biphasic sleep is seen every day, usually after lunch. This phenomenon was thought to be a product of the vast number of calories we consume, followed by redistribution of our blood circulation from our brain to our gut, allowing better absorption of the nutrients. We now know that is not the only explanation. The after-lunch dip in alertness is seen even in people who do not eat in these afternoon hours and even in people who fast for the entire day.

So could we benefit from switching from a monophasic to a more natural biphasic sleep?

I had trouble with falling and staying asleep for quite some time, so I put this theory to the test.

I noticed that at whatever time I lie in bed, I feel unable to fall asleep at a reasonable hour, and consequently wake up feeling tired. Instead of taking a nap in the afternoon when I felt most tired, I always pushed myself to stay awake, telling myself that I would fall asleep in the evening somewhat earlier. To my disappointment, I always failed in that task and usually ended up with chronic sleep deprivation. I struggled for a while with this vicious cycle, but after some time decided to try a biphasic sleep schedule.

It was one of the best ideas and best changes I made in my life.

Falling asleep in the afternoon felt incomparably more natural than struggling to go to sleep as early as I could. I felt more energetic and positive throughout the day, my focus improved, and to my biggest surprise, I could fall asleep much faster and didn’t wake up during the night as I usually did.

The problem I was worried about the most was the fear of not getting enough sleep during the night. In my mind, I thought that if I slept for 3 hours during the day but only 5 hours during the night, I wouldn’t be able to get up for a morning lecture. But something completely contrary happened. I was having so much energy, it was the first time since I was a child that I woke up in the morning fully refreshed and ready to face the day head-on. Biphasic sleep was a game-changer for me. I could fall asleep so much more easily, not only during the day but also during the night.

Another positive aspect of this split sleep schedule was a psychological one. I felt that day was somewhat longer, but also split into two timeframes. In the morning, I used my energy for commuting to my medical school, listening to lectures, caring for the patients in my clinical practice, but also for socializing with my colleagues and family once I came home. The other part of the day was reserved for studying. That afternoon nap cleansed my mind of all the troubles and events I was involved in in the morning, but also provided me with a boost of energy, much needed for a study session.

Sadly, not many of us can fit an afternoon nap into our increasingly busy schedules. With a tear in my eye, my biphasic sleep came to an end once the medical school I go to changed its curriculum to a more chaotic, 8 hours of lectures, everyday schedule.

Since then, I got back to a monophasic sleep pattern (with many changes made, of course), but every once in a while, I sneak in that sweet afternoon nap just to honor its greatness.

Summary:

🧬 Why We Sleep Differently

• While 7-8 hours of sleep is the current ideal, biological differences mean some thrive on less or more.
• The terms “Night owl” and “Morning lark” reflect real genetic variations in sleep patterns, shaped by evolution to minimize group vulnerability at night.

🕰️ Sleep Before the Industrial Age

• Historically, humans practiced biphasic sleep: sleeping for a few hours, waking for a bit, then sleeping again until dawn.
• Cultural practices like Mediterranean siestas and the common post-lunch energy dip further support the naturalness of split sleep.

🌙 A Personal Sleep Experiment

• I struggled with falling asleep and feeling rested.
• After shifting to a biphasic sleep routine, napping in the afternoon and sleeping fewer hours at night I experienced:
  • Better energy
  • Sharper focus
  • Easier, deeper sleep
  • A psychological sense of a “longer” and more productive day