Here’s Why We Sleep


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Believe it or not, sleep is still little understood.

But that’s changing. In the last ten years there have been many studies on the purpose of sleep. Here’s some of their findings:

  • Sleep Repairs Cell Damage – When we sleep, our cells repair themselves. Old, end of life cells, are replaced by new cells. Damaged cells are repaired. The Glymphatic System is called into action, sending lympatic fluid where it is needed in order to remove dead cells.
  • Sleep Creates Memories – During the REM stage of sleep, new information we acquire during the day is looped back and forth, thousands of times, between the hippocampus and the neocortex.  Once stored it becomes part of our long-term memory. Long-term memory is also known as Long-Term Potentiation.
  • Sleep Clears Out Waste Material Within Each Cell – Glucose or Ketones are the primary fuel source for every cell within our body. This fuel enters every cell. It is then converted to ATP, which the mitochondria (power plants within each cell) use to power the cell. During this conversion process, Free Radicals (free electrons) result. Free Radicals represent dangerous waste material. Unchecked, they will bounce around inside every cell and can damage the Nucleus (where our DNA and genes reside – causing cell mutations) or they can damage the inner lining of the cell wall. In order to prevent them from mutating or damaging the cell, these Free Radials must be removed. During sleep, oxygen is deployed to soak up these Free Radicals, carry them outside the cell wall and into our blood. Our blood then carries them to the lungs, converts the Free Radical-soaked oxygen into carbon dioxide, which is then exhaled into the environment. Goodbye waste.
  • Sleep Helps Grow & Repair Muscles – During sleep, the pituitary gland releases a growth hormone, which stimulates muscle growth and repair. 
  • Sleep Erases Memory – During sleep, the brain will do a self-diagnosis with respect to stored information. Information (memories) it deems irrelevant, are erased – forever.
  • Sleep Grows & Distributes New Brain Cells – During sleep, new brain cells are created and dispersed to various parts of the brain, where they are most needed.
  • Sleep Oxygenates the Eyes – The purpose of Rapid Eye Movement (one of the 5 sleep stages) is to oxygenate our eyes. This is the only way our eyes receive the oxygen they need to survive.
  • Sleep Restores Willpower – When willpower is depleted, we become unable to focus and think clearly, causing us to be distracted and to make poor decisions. Sleep helps to restore our depleted reserves of willpower.
  • Sleep Reduces Inflammation and Helps You Think Clearer – Sleep slows down your Sypathetic Nervous System, reducing stress. This not only helps you think clearer but also helps to reduce inflammation throughout the body. Chronic inflammation is associated with all sorts of diseases, including cancer and heart disease. Individuals who do not get enough sleep make poor decisions, suffer from chronic inflammation and are susceptible to disease.
  • Sleep Cleans Brain Cells – Amaloid is a protein that builds up on the neural receptors of every brain cell. The uncontrolled build up of Amaloid is believed to result in Alzheimers. Sleep flushes away these Amaloids.

How much sleep do you need?

The average adult requires between four to six sleep cycles a night. Each sleep cycle is composed of five separate levels of sleep: alpha, theta, delta, rapid eye movement (REM) and then back to theta. The first three sleep levels last approximately 65 minutes. REM lasts 20 minutes and the final level of sleep, theta, lasts 5 minutes. So, each sleep cycle lasts about 90 minutes. Four sleep cycles is about six hours of sleep. Five sleep cycles is 7.5 hours of sleep and six sleep cycles is approximately nine hours of sleep.

The number of hours you sleep is less important than the number of complete sleep cycles your brain requires every night. Five sleep cycles a night, or 7.5 hours, is considered optimal.

This is why some individuals require more or less sleep than others. It all depends on how many sleep cycles your brain requires each night.

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Thomas C. Corley About Thomas C. Corley

Tom Corley is a bestselling author, speaker, and media contributor for Business Insider, CNBC and a few other national media outlets.

His Rich Habits research has been read, viewed or heard by over 50 million people in 25 countries around the world.

Besides being an author, Tom is also a CPA, CFP, holds a master’s degree in taxation and is President of Cerefice and Company, a CPA firm in New Jersey.
Phone Number: 732-382-3800 Ext. 103.
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  1. Hello Thomas! This was a great summary of what happens when we sleep! I was just talking about the mitochondria on a video yesterday and the release of electrons and how oxygen grabs it (which effectively causes oxidation of our cells – much like an apple browns when exposed to air). This is also why its important to consume enough antioxidants in our diet, as this aids in keeping those harmful free radicals in check and allow oxygen to do it’s job…to oxygenate versus oxidize our bodies.

    Even though it’s a natural process of mitochondria to release unused electrons (harmful free radicals) from the food we eat we also have the means (life saving antioxidants) to correct it….but they HAVE to be consumed from a bio-available source.

    Thanks for all you do, Tom!

  2. Lisa Schreiber says:

    Hi Tom…thanks for this excellent summary of why it’s so crucial to get a good night’s sleep! Your ability to explain complex material in easy to understand terms always amazes me! (Now if you could just convince my husband to catch some more z’s!)

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