EVOLUTION OF SLEEP: WHY DO WE WASTE 36 % OF OUR LIFE TIME IN SLEEP? - PART 1

WHY DO WE SLEEP? ( By Sanjeevi Ramamoorthy)

We Humans waste 36 % of our life time in sleep. WHY CANT WE AVOID SLEEP WHICH WILL GIVE US EXTRA 32 YEARS (IF WE LIVE TO 90 YEARS) ? What is the necessity of Sleep through the eyes of Neuro Science and Bi logical Evolution?

After 50 years of research, William Dement, founder of Stanford University's Sleep Research Center, replied to the above question that , "As far as I know, the only reason we need to sleep that is really, really solid is because we get sleepy". 

MYTHS ABOUT SLEEP:

1. Myth No 1: Sleep helps body to Conserve Energy

 Wrong. Energy required for Metabloism if we sit idle is approx around 95 Kcal / Hr where as it is  90 Kcal/ Hr during Sleep. 8 Hr Sleep will save approx 50 K calories only  ( Equal to calories in one small cup of Tea). Negligible. In some Animals, energy required to sleep is more.

2. Myth No 2: Brain needs rest

Wrong. In fact, brain is very much active ( emitting Alpha wave having 8 - 13 Hz) during  REM ( Rapid Eye Movement) Sleep than normal awakening state.Metabolism of brain increases during sleep.

THEN, WHY Evolution  had ensured that all Animal Kingdom including Humans Sleep and Dream?

Sex & Survival are the two fundamental forces which drive the "Bilogical Evolution". But Sleep increases the risk of predation ( our ancestor lived among predators. Sleep increased the risk of being prey to the predators). THEN,  WHY BIOLOGICAL EVOLUTION CREATED SOMETHING CALLED SLEEP ? There is no single species in this world ( out of total 8.7 million species) which dont sleep.

WHAT IS CALLED SLEEP?

Sleep is the altered conscious state in which sensitivity to the external stimulus is limited / partial (where as in coma condition, responsiveness to the external stimulus is null). But, our Sub - Conscious mind is very much active during the sleep state.

( Note: Science is yet to unlock the mystery of How Consciousness is being created in our Human Brain.)

(Vsuce Video on Sleep and Dream)

Sleep normally happens in 90 Mins Cycle. This 90 Mins Cycle has four stages as classified by American Academy for Sleep Medicine (AASM)

Stage 1: It is  Half Sleep State in which our Neuron Cell emits the Theta Waves ( 4 - 7 Hz). Approx, we spend 10 % our Sleep in this stage. Time in each cycle:  10 Mins
                             
Stage 2: In this stage, our sensitivity to surrounding will further come down. We spend normally 50 % of our sleep in this stage. Time in each cycle: 45 Mins.

Stage 3 & Stage 4 or Slow Wave Sleep: This stage is called Deep Sleep State in which our sensitivity to the surrounding is very much limited and our brain cells emit Delta Waves ( 0 - 4 Hz). Normally Nightmares comes in this stage. Time in each cycle: 15 Mins

After Stage 3 & 4 , we again go back to Stage 2 before proceeding to the most important stage called Rapid Eye movement or REM Sleep

REM ( Rapid Eye Movement Stage) Sleep: It is called Dream State in which most of our dreams happen. Our brain emits Alpha Waves ( 8- 13 Hz) equal to state of wakefulness Time in each cycle: 20 Mins.

This 90 Mins cycle repeats throughout the night.

                                                   ( Sleep Cycle in Normal 8 Hrs Sleep)

                                        
                                            ( Brain Waves Pattern during various sleep state)

OK. BUT WHAT IS THE NECESSITY OF SLEEP ( Altered Consciousness State) FOR THE SPECIES? WHAT HAPPENS INSIDE OUR BRAIN DURING SLEEP? CAN MODERN SCIENCE HELP US TO AVOID SLEEP SO THAT WE CAN SPEND 32 YEARS IN USEFUL WAY RATHER THAN SLEEPING?

NECESSITY OF SLEEP: ( NEUROSCIENCE OF SLEEP)

                                          ( Nova's Documentary on Sleep and Dream)

1. Growth and Cell Healing Hormones:

In some studies, it has been proved that growth Hormone and Cell Healing Hormones are being segregated during sleep. But it is not the major thing. 36 % of our life time is huge cost to pay for this Harmones which we can be artificially injected in return for Wake fullness.

2. Sleep & Memory:

Scientist strongly suspects that  the main purpose of the evolution of sleep and dream could be the learning, Creativity & Organisation of Memory ( learned in day time). Memories are stored in the  form of connection between various neurons cells in our brain. It seems this neuron cells follows the specific pattern of firing between them for each memory.

Studies have found that our subconscious mind recreates the memory (learned during the day time) inside our brain during our sleep. It is being hypothesized that NREM ( Non Rapid Eye Movement ) Sleep helps our brain to compare these newly learned memories with previous one ( Organizing).

REM Sleep (Rapid Eye Movement) stage actually acts as a Testing Field where this newly organised memories are being tested for the various permutation and combinations which leads to creativity,Innovation & better learning (Some studies in fact have proved these practically).

But, modern science is not able to explain why organisation of memory and process of creativity cant happen in wakefullness state since we lack the complete understanding of the Human Brain.

OTHER INTERESTING QUESTIONS ARE

1.WHAT ARE DREAMS? 

2.WHAT IS THE CONTRIBUTION OF DREAM TO OUR MEMORY PROCESSING AND ITS RELATION BETWEEN SLEEP? 

3.CAN WE REALLY CONTROL THE DREAM OF OTHER PEOPLE AND STEAL DATA LIKE IN THE MOVIE INCEPTION?

4. WHETHER TIME DILATION IS HAPPENING IN DREAM?

                          ( LET'S SEE IN THE PART 2 OF THIS ARTICLE)

IMMORTALITY: CAN SCIENCE MAKE US IMMORTAL?:

How Close Are Humans to Immortality?                     (S.Ramamoorthy)

All religions have been preaching that death is the ultimate truth. Is it so? If it is, how one species called "Turritoposis dohrni ( type of Jelly fish)" achieved Immortality? How Close are scientists from achieving Immortality? Can we ( Humans) live forever without death? Let see....

                                                  (BBC Documentary on Immortality)

WHAT IS CALLED AGEING?

Our body is made of trillions number of cells.  50 - 70 billions old cells die every day in our body and these are being replaced by New Cells created through the process called Cell Division. As long as, this process ( cell division ) continues, we will be healthy and live forever.

But problem is that cells can't simply divide forever. One Human body Cell can divide maximum between 50 - 70 times only. This is called Hayflick Limit. Beyond this, cell will cease to divide ( This is called Ageing) and eventually dies.

WHY CELL CANT CONTINUE TO DIVIDE FOREVER?

We know that each Human  Cell has 23 pairs of Chromosome ( Group of DNA, Genes, Proteins). These each chromosome is protected at it's end by something called "Telomere" ( Repetive Nucletoide Sequence) which ensures the exact replication of Chromosome ( necessary to pass the genetic information to new cell) during each Cell Division.

For understanding purpose, we can compare the Telomere with the  plastic Tips on the both end of Shoe Lace ( in this case, Chromosome). Without plastic tips on its end, shoe lace will get frayed and it will not stick together.  Like this, exact replication of chromosome in the cell division is not possible without telomearse at its end.

   

But the problem is that length of the Telomere is being shortened during each Cell Division. After approx 50 - 70 cell division, length of the Telomere will reach the critical level which prevents further cell division( since exact replication of chromosome is not possible)  resulting in the ageing process.

HOW TO INCREASE THE LENGTH OF TELOMERE?

Cancer is nothing but unlimited division of cell. It means that cancer cell has already found the solution to increase the length of Telomere which allows cells to divide forever (IMMORTALITY). Enzyme used by Cancer Cell to increase the Telomere is called Telomearse. Embroyic Stem Cell also uses the same method to achieve the unlimited cell division.

Scientists are now researching how to use this Enzyme called "Telomearse" used by cancer cell & Embroyic stem cell to achieve the unlimited cell division ( IMMORTALITY) in normal cells also.But problem is that these enzyme has the potential to turn normal cell to cancerous cell which is the main constraints for the scientists.

IS THERE ANY SPECIES IN THIS EARTH WHICH LIVE FOREVER?

Yes. Process of Bi logical Evolution has successfully created one species called Turritopsis dohrnii, the immortal jellyfish ( one type of Jelly Fish found in Medeterrian Sea and Japan Sea) which is immortal in nature ( but vulnerable to predation, injury and disease). 

Process used by the above species to achieve immortality is called "Transdifferentiation" which allows jelly fish to go back from adult stage to infant stage again ( Age Reversing ) and infant age to adult stage ( Ageing) endlessly.

2008 Hollywood movie titled " The Curious Case of Benjamin Button" starred by Brad Pit was based on this concept only.

OTHER METHODS FOR IMMORTALITY:

A.Calorie Restriction:

Some scientist have found that calorie restriction ( eating Less) is slowing the ageing process and will increase the life span by about 30 % . It has been successfully tested in rats and some humans.

Problem with this method is that It may increase the lifespan but wont achieve immortality.

B.Anti Oxidant:

There is another one theory called "Free Radical Theory of Ageing" which tells that real cause of ageing is " Reactive Oxygen Species (ROS)" ( ROS is nothing but highly reactive radical atom / molecule which has unpaired electron in its orbit ) created in our cell during the process of oxidation. These ROS will further create chain reaction which will cause irreparable damage to the DNA and proteins eventually killing cell.

Solution is to take Anti Oxidants ( Vitamin A. E ,C) in our food which will control this ROS and in turn will slow ageing process.

CONCLUSION:

Modern science is just decades away from achieving Immortality. But Big Question is that whether Immortality will be Boon or Curse?