Sleep.......💤💤

“Innocent sleep. Sleep that soothes away all our worries. Sleep that puts each day to rest. Sleep that relieves the weary laborer and heals hurt minds. Sleep, the main course in life's feast, and the most nourishing.” - William Shakespeare, Macbeth 

Man spends 1/3rd of his life, or ought to, in an act that is more mysterious than any other biological process in a human's life. Barring some marine invertebrates, and infants of dolphins and whales, most multicellular organisms are known to sleep. Even plants have a circadian rhythm that we know of. So what is sleep and why do we need it, more so, among humans?

Sleep is defined as the condition of body and mind that typically recurs for several hours every night, in which the nervous system is relatively inactive, the eyes closed, the postural muscles relaxed, and consciousness practically suspended.

The physiologic changes during sleep can be simply explained thus:

Neuronal Transitions: When you fall asleep, thousands of neurons in your brain switch from a waking to a sleeping state, sending signals throughout your body. These transitions are crucial for maintaining overall health.

Cardiovascular and Immune Reinforcement: Although the full biological role of sleep remains a mystery, research suggests that it reinforces both the cardiovascular and immune systems. During sleep, the body undergoes repair and maintenance, supporting overall well-being.

Metabolic Regulation: Sleep also plays a role in regulating metabolism. While the exact mechanisms are not fully understood, energy restoration occurs during sleep, allowing the body to recharge for the day ahead.

Brain Functions: Sleep isn’t merely a passive state. It’s a highly active process where the brain processes the day’s events, consolidates memories and rejuvenates itself. Brain waves and other physiological functions exhibit characteristic patterns during different stages of sleep. Sleep happens in stages from wakefulness to non-rapid eye movement sleep (NREM) and to a deeper phase of Rapid eye movement sleep (REM). The body goes into deep relaxation in stage 2 of NREM sleep and all voluntary muscles are paralysed in REM sleep. This is the only period during which all the postural muscles are completely relaxed in the human body during the day.

There has been through the ages a lot of interest in how sleep actually works and why it is required. Some popular opinions on social media is that we are wasting our life when we are snoozing, when we should be working more hours ( hustle, is what they call it , I guess). Well, unfortunately the science of sleep, for which Hall et al got a Nobel Prize, does not agree with this opinion.

Jeffrey C. Hall, Michael Rosbash, and Michael W. Young

Jeffrey C. Hall, Michael Rosbash, and Michael W. Young we jointly awarded the Nobel Prize in Physiology or Medicine in 2017 for their discoveries of molecular mechanisms controlling the circadian rhythm. Man has always been fascinated by the changes in the world as the sun sets. The 18th-century astronomer Jean Jacques d’Ortous de Mairan studied mimosa plants and found that the leaves opened towards the sun during the daytime and closed at dusk. With time scientists and observers found that not only plants, but also animals and humans, have a biological clock that helps to prepare our physiology for the fluctuations of the day. This regular adaptation is referred to as the circadian rhythm, originating from the Latin words circa meaning “around” and dies meaning “day”. Previously scientists had discovered the "period " gene, whose mutation caused a disruption of circadian rhythm in flies. Hall et al isolated the period gene and discovered that PER, the protein encoded by period, accumulated during the night and was degraded during the day. Thus, PER protein levels oscillate over a 24-hour cycle, in synchrony with the circadian rhythm. This is easily explained as the accumulation of a protein (called a toxin in ancient texts) during the night and its breakdown during the day, thus keeping the rhythm intact.

Sleep is an integral part of our life, as it cannot be consciously experienced. Its effects can only be appreciated when it is lacking. Sleep is a great cleanser in this ever-over-achieving society and rids one of stress and trauma built over the years. The physical and physiological changes from a good sleep are worth experiencing every day.