For most of human history, the smartest among us have hypothesized about why we sleep, what happens when we sleep, and what sleep does for our minds and bodies.   After several millennia of conjecture and theory, the science of sleep came alive at the beginning of the 20th century.  Advances in other areas brought us the scientific method and the concept of proving theory with reproducible experiments.  These scientific principles coupled with important discoveries changed almost every accepted theory about sleep.  It was the beginning of a new age for the science of sleep.

What Took So Long?

Humans have slept since the race began, which calls to question why it took so long for us to make real scientific breakthroughs in this area.  It is easy, in retrospect, to see why the science of sleep had previously been so elusive.  Most scientists rely on observation but we cannot observe ourselves when we are sleeping.  Unfortunately, examining or observing the sleep of others without modern technologies also provides very little information or insight into what is actually going on inside their bodies and their minds.

What Changed?

This all began to change in the first half of the 20th century.  The first real advance came in the area of chronobiology when two scientists noted a peculiar behavior in bees that would lead to the discovery of our circadian rhythm. That discovery enhanced our understanding of how biology and our internal biological clocks dictate when we sleep and when we are awake.

The next advances that helped push sleep science to the next level were in electrophysiology.  Advances in using these techniques including the use of the electroencephalogram (EEG) allowed scientists to get their first look at what was going on inside our heads when we were sleeping.  These discoveries dispelled one of the most widely accepted “truths” about sleep, that our brains were as silent and still as our bodies.  The EEG showed that our brains are actually very active while we sleep and helped scientists and researchers to understand that our brains were most active during those times that rapid eye movements were also observed.  This stage of sleep, what we call REM sleep today, helped pave the way to defining the many phases of sleep that are part of the foundation of sleep science today.

Other advances in neurochemistry and neurophysiology helped pave the way for the sleep research conducted today.  Initial research and hypotheses about how the states of sleep and wakefulness were regulated, what parts of the brain are involved in this regulation, and the existence of sleep disorders provided the foundation for modern sleep science to take off during the second half of the 20th century.

Thanks to modern day science and technology, our understanding of sleep in the last 60 years has increased more than in the last three millennia.  In fact, it seems to be constantly changing as new studies and research findings are published on almost a monthly basis.  As we learn more about the role sleep plays in our health, our performance, and even our longevity, it may finally be recognized for the vital bodily function that it is.


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