Why do we sleep?

Why do we sleep?
Last article we learned some of the basics of sleep, including what makes us sleep.  Today I thought we could talk about why sleep is so important, and how much sleep we really need.

Why is sleep so important?
The truth is that we don’t really know enough about why we sleep.  However, we do have good research to show many of the benefits of sleep, and the problems associated with too little sleep.

How does sleep affect your brain function and emotional health?
Sleep is one of the things that keeps your brain functioning properly.  Sleep deficiency actually changes the activity in some parts of the brain.  Studies have shown that getting a good night’s sleep improves your ability to learn.  Whether that is learning to play an instrument, a new language, perfecting your tennis game, learning math or reading, it is all improved with sleep.  Other benefits shown in research include improved attention, decision making, problem solving, and creativity.  Sleep deficiency has been linked to depression, suicide, and risk-taking behavior. 

There is also a direct link between sleep and the creation of long-term memories.  You have untold numbers of short term memories every day.  While you are sleeping, your brain determines what information can be discarded, and what is useful enough that it should be stored as long-term memories.

If you are not getting enough sleep, your brain cannot move short-term memories into long-term storage.  Your brain also uses the time during sleep to clear out the clutter of unimportant information gathered throughout the day, in order to prepare for another day of learning. 

What about your physical health?
Here are a few of the physical problems associated with sleep deficiency…

  • Increased risk of heart disease, high blood pressure, kidney disease, diabetes, and stroke.
  • Increased risk of obesity, through several mechanisms.
  • Lower immune function, leading to trouble fighting common infections.
  • Sleep is important to support healthy growth and development in children and teens.

What about productivity, performance, and safety?
People who are sleep deficient are less productive at work and school, even with a loss of only 1-2 hours a night. They take longer to complete tasks, have a slower reaction time, and make more mistakes.
If you are sleep deficient, you can have brief moments of sleep during the day, called microsleep.  Have you ever driven somewhere and then realized that you don’t remember part of the trip?  Maybe you had a brief episode of microsleep.

Studies also show that being sleep deficient harms your ability to drive as much as, or maybe even more than, being drunk. Sleep deficiency has been linked to numerous tragic accidents involving planes, trains, and automobiles.  An NTSB study focused on the effects of alcohol and drugs in trucking accidents actually showed that sleep deprivation was a much larger problem, with 40% of fatal accidents due to a simple lack of sleep.

How much sleep do we need?

Age Recommended Amount of Sleep
Infants 4-12 months old 12-16 hours a day (includes night time and naps)
1-2 years old 11-14 hours a day (includes night time and naps)
3-5 years old 10-13 hours a day (includes night time and naps)
6-12 years old 10-12 hours per night
13-18 years old 9-10 hours per night
Adults over 18 7-8 hours per night

I hope I have convinced you of the significant importance of sleep on your health.  Next time, we will talk about some strategies for getting the sleep that you need.

If you have any more questions just Ask Hanna, our health advisors are here to help.

Dr. Anita Bennett MD – Health Tip Content Editor
Image: ©Shutterstock / ImageFlow

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