Essential Sleep

1. Sleep Complexity

In Ramayan, Kumbhkarna is described as a demon who had a great appetite, was very powerful and used to sleep for six months at a time. And when he was asleep, it was almost impossible to wake him up. That’s why we have metaphor “Kumbhkarna’s Sleep” for prolonged inaction of somebody who is powerful.

“?? ???? ?? ?? ???? ??” - this is a line from the famous poem “?? ??? ????????” by Vanshidhar Shukla. If read in isolation, this may give an incorrect impression that sleeping is a hinderance to your growth.

We spend about one-third of our life sleeping. It is a normal body process that allows our body and brain to rest. For most people, it’s just a matter of getting comfortable, closing your eyes and drifting into slumber. So, sleep looks deceptively simple. But despite how simple it seems, sleep is one of the most complex and mysterious body processes known to science. Even Researchers and experts struggle understanding it because of the mysteries surrounding how and why we sleep and what happens to us while we sleep.

2. What happens when we sleep?

Before the 1950s, most people believed sleep was a passive activity during which the body and brain were dormant. But subsequent studies have revealed that sleep is a period during which the brain is engaged in a number of activities necessary to life. Hence, sleep is essential for life and not an overhead.

Your body cycles between being awake and asleep throughout each day, with certain processes only happening when you’re asleep. When you’re asleep, your body “powers down” and most body systems — including your brain — become less active.

Some of the key things that happen while you’re asleep include:

• Energy Conservation and Replenishment - While you’re asleep, your body uses less energy. That lets body cells conserve energy and stock up for the next day.
• Self Healing and Repair - Being less active makes it easier for your body to heal injuries and repair issues that happened while you were awake.
• Memory Consolidation - While you’re asleep, your brain does a memory consolidation – linking information received while awake in the form of short term memories, with previous experiences and puts the important and useful information into long term memories. And, discards the trivial short term experiences.

3. Sleep Cycle

You may not know it, but while you're asleep on a night, you're going through multiple sleep cycles. And, in each sleep cycle, you're going through four sleep stages.

Stage 1 (N1) Light Sleep

Lasts from 1 to 7 minutes. In this stage you're moving from wakefulness to sleep. Your muscles start to relax. Your eye movement starts to slow down, your heartbeat slows down, and your breathing slows down. As you're sleeping very lightly, it's very easy to wake up during this stage – like due to a small movement, or a light or a sound. If you wake up, you could feel like you just came out of a deep sleep and feeling very groggy.

Stage 2 (N2) Intermediate Sleep

Lasts for about 25 minutes. There is further slowdown of your heartbeat, breathing and eye movements. Your muscles relax further, brain activity starts slowing down, as well as your body temperature. The sleep in this stage is deeper than N1 stage.

Stage 3 (N3) Deep Sleep

Lasts for 40 minutes. Also known as slow wave sleep. In this stage, your body relaxes even more. Your muscles and bones are recovering and growing. Your immune system is strengthened. Your breathing and heart rate are very slow. The brain waves show a clear pattern of slowed activity that is markedly different from waking brain activity.

The deep sleep plays an important role in recovery of the body as well as effective thinking and memory. It is the deepest part of sleep when it's hard to wake up, even if light goes on in your room or you hear a loud noise.

Stage 4 REM Sleep

REM stands for Rapid Eye Movement as this is the sleep stage when your eyes are moving behind your eyelids. Also, this is when there is a lot happening in your body - your heartbeat increases, blood pressure goes up, breathing increases and becomes more irregular. At the same time, your legs and your arms get paralyzed.

During this time, brain activity picks up significantly, and most of the body — except the eyes and breathing muscles — experience temporary paralysis.

While you can dream in all four stages, your most vivid dreams are going to happen during stage four. At the same time, during stage four, a lot of learning is happening. Your memories are being consolidated and indexed, and your mood is also being regulated.

Stages 1 to 3 (N1, N2, N3) put together are also called non-REM Sleep in contrast to Stage 4 which is called REM Sleep.

These 4 stages form one sleep cycle that goes for approx. 90 minutes. So, during a night’s sleep, one goes through these sleep cycles, multiple times. But with each cycle you spend less time in the deeper stage 3 and more time in REM sleep. On a typical night, you’ll cycle through four or five times.

4. How Sleep Occurs? - Two-Process Model of Sleep & Awake

The sleep-wake cycle is regulated by two separate biological mechanisms commonly referred to as Process S and Process C:

1. Process S (Sleep-wake Homeostasis) causes a pressure to fall sleep. It is the accumulation of sleep-inducing substances like adenosine in the brain.

It's really like a balloon which is flat in the morning when you wake up – all sleepiness drained out. As you go throughout the day and use your energy, it gets filled up. And when it reaches a tipping point, you go to sleep and sleepiness again gets drained from the balloon. It effectively reminds the body that it needs to sleep – so the longer you’ve been awake, the stronger your desire for sleep becomes.

2. Process C (Circadian Rhythm) dictates the daily rhythm of sleep.

What is Circadian Rhythm?

Your body needs to follow a schedule because there are many functions that your body needs to perform every single day. But your body cannot perform all of those functions at the same time. And some functions only make sense at specific times.

The Circadian Rhythm is scheduling and optimization of your body functions based on your body’s internal Biological Clock. Our body cells produce their own 24-hour Biological Clock by accumulating and breaking down proteins in a cycle that takes around 24 hours.

The working of this 24-hour cycle and its connection with circadian rhythm and human health has been extensively studied by the trio of Jeffrey Hall, Michael Rosbash and Michael Young who have won the Nobel Prize as recently as in 2017 in Physiology/Medicine for their work on this subject.

The circadian rhythm regulates body’s activities like sleep patterns, feeding patterns, core body temperature, brain wave activity, and hormone production over a 24-hour period. Sleep is promoted by hormone Melatonin, which is naturally produced as light exposure decreases.

These two (process S and process C), work together to create a balanced sleep-wake cycle. While you’re sleeping, the sleepiness rapidly dissipates while melatonin is produced as light exposure is reduced. By the early morning, melatonin secretion stops and the circadian alerting system begins. This will overcome the existing sleep drive, thus triggering the body to wake up.?

Even though this model dominates the scientific understanding of sleep regulation, external factors such as work schedules, genetics, food, stress, and exercise also influence sleep times.

5. Reason for Kumbhkarna’s abnormal Sleep

We have heard legend about the reason for Kumbhkarna’s Sleep. But now, the scientists claim to have found the reason behind the Kumbhakarna’s oversleeping and great appetite. In an article “Kumbhakarna: Did he suffer from the disorder of the hypothalamus?” published in Indian Journal of Endocrinology and Metabolism and also National Library of Medicine (US), doctors said Kumbhakarna might have suffered from hypothalamic obesity, which is caused due to abnormality in the region of brain called hypothalamus and controls appetite.

It could have been caused due to brain tumor, inflammatory conditions such as tuberculosis or head injury which is treatable in most cases, said Dr Om J Lakhani, co-author of the study at Sir Ganga Ram Hospital conducted on a 50-year-old patient with similar symptoms.

6. Sleep and Learning

Studies have found that you need sleep after learning to preserve those new memories. Studies also indicate that you need sleep before learning, to actually prepare your brain, almost like a dry sponge ready to initially soak up new information. Without sleep, the memory circuits of the brain become waterlogged and you can't absorb new information.

What neuroscience says?

The hippocampus is part of the brain’s limbic system. It plays central role in our emotional experiences. At the same time, it also plays important role in memory consolidation. It is like the information inbox of your brain, receiving new memory files and holding on to them.

Without sleep, the emotional circuits of our brain become hyperactive and irrational. Most of us would have experienced weird or lack of emotions when we are sleep deprived. The brain scans have confirmed reduced learning related activity under sleep deprivation.

Studies have indicated quite significant 40% drop in the ability of the brain to make new memories without sleep. This should be frightening considering what we know is happening to sleep in our education populations right now. It could be the difference between acing an exam and failing it miserably.

7. Sleep Technology

Considering the criticality of sleep for our wellbeing, many companies are coming up with technology based solutions that are claimed to help in improving the quality of sleep. Sleep Technology refers to gadgets and apps designed to track, improve and promote healthy sleeping habits - also called good sleep hygiene.

Sleep Apps – some sleep apps offer meditation and breathing programs, stretching and even bedtime stories. Some offer built-in monitors that track sleep data with the added bonus of activity, heart rate and body temperature tracking. There are also apps that use Cognitive Behavioral Therapy techniques to help improve sleep.

Wearable sleep trackers - use various metrics to track sleep, including heart rate, oxygen levels and physical movement. Sunrise alarms clocks can make waking up much more pleasant through use of light and relaxing sounds. Smart sleep masks come equipped with sensors to track eye movements, which helps to explain sleep quality.

But the long-term efficacy and safety of use of such technology is yet to be ascertained. It also goes against the very paradigm of 'keeping technology away' for a good sleep!

8. Sleep and Hindu Philosophy

The Upanishads mention that during deep sleep (sushupti), jivatmas are united with the Paramatma, which means they are not aware of themselves or of their resting in Paramatma. Once they wake up, they become aware of their identity. They are like rivers coming from different directions entering the sea. Once they enter, you cannot pinpoint where in the ocean the water from different rivers is located.

Anantashayanam: The Cosmic Dream Sleep of Lord Vishnu

Lord Vishnu is worshipped in his reclining YOGA NIDRA pose, relaxing on the bed of Anant-shesha (huge serpent) in Kshir Sagar (shoreless cosmic ocean). Lord Vishnu maintains the universe with his imagination in this form. He is more awakened and creative while seemingly asleep.

Lord Vishnu is the nourisher of all. He has to be more conscious than anyone else for making the world flourish and evolve. It is like our physical body which is better nourished when asleep.

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