Why Doctors Recommend 7-9 Hours of Sleep Each Night

Why Doctors Recommend 7-9 Hours of Sleep Each Night I Mirra Skincare

One of my favorite words in the whole world: sleep! From despising sleep as a child to learning to cherish every moment of it, sleep transforms throughout your life. Whether you are the type of adult who needs no more than 4 hours of sleep and a cup of coffee in hand, or you are that person who cannot function without 10 hours, everyone differs on this topic. 


1. Why do we need sleep?

2. Circadian rhythm

3. REM

4. What happens when we don't sleep?

Key Points

  • When you sleep, your body is able to restore and prepare you for the day in ways it physically can't when you're awake.
  •  Your circadian rhythm and REM cycle determine how and when you get the best sleep.
  • Without enough rest, your mind and body can't function.

No matter what feels perfect for you, sleep is nonetheless a crucial part of every human's routine. Not only is sleep essential to functioning in the social world, but it is a part of our basic needs to stay healthy. No wonder there are so many experts researching sleep habits, the ideal amount of sleep, and doing sleep studies on patients! 

Why do we need sleep?

But WHY do doctors specifically recommend 7-9 hours of sleep, you may ask? First, it is important we go over why we need to sleep. Some benefits of sleep for the human brain and body are:

  • Without sleep, you can’t form or maintain the pathways in your brain that allow you to learn and create memories
  • Sleep helps your nerve cells communicate with one another
  • Without sleep, it makes it difficult to focus and/or concentrate
  • Sleep plays a role in fighting to keep toxins out of the brain that build while you are awake
  • Sleep impacts almost every tissue in your body; without it, almost everything suffers

Circadian rhythm

To understand how sleep impacts us and why doctors recommend a certain amount of hours of sleep to reach an ideal health, it would be beneficial to go over the circadian rhythm and REM cycle. Sound familiar? Yeah, you probably last learned about it in high school, so let’s refresh our memory. 

First off, your circadian rhythm impacts a range of daily functions from daily changes in wakefulness to body temperature, metabolism, and the release of hormones. Circadian rhythm takes in environmental cues such as light and temperature and reacts accordingly to these cues regarding sleep. Circadian rhythm allows you to know when to rest and go to bed, and it also knows when to wake up even before your alarm will.

Some people refer to this concept as your body’s biological clock, which is based on a roughly 24-hour day. This is the reason why your brain and body get tired around the same time every night and you may be able to wake naturally without an alarm most days. 


Once you fall asleep, you are looking at a different sleep concept called the sleep cycle. Within the complete sleep cycle, there are two types of sleep involved being rapid eye movement (REM) sleep and non-REM sleep. No-REM sleep has three different stages within that level of sleep. Here is what the cycle looks like: 

Stage 1: In this first stage, your brain is switching over from being awake, to being in the first stage of non-rem sleep. Within this stage, your body is starting to relax, your heart beat slows down, you may experience body twitches, and you are experiencing light sleep. Surprisingly, this stage only lasts several minutes!

Stage 2: In this stage, you are beginning to enter a more intense light sleep and your body is still relaxing completely. Your body temperature may drop and your breathing will slow. In this stage, you are still in a fairly light stage of sleep.

Stage 3: In this last non-REM stage of the sleep cycle, you are approaching REM sleep. This will be the point in which your body is fully relaxed, and this is also the stage that you need in order to feel completely rested when awakening. Brain waves become even slower and at this point, it may be harder to wake you. 

REM: In this stage of sleep, your brain activity looks more closely like it does when you are awake. This is because REM sleep is the stage in which you are able to dream and your heartbeat and breathing are sped up. Your eyes also move side to side rapidly behind your eyelids in this stage, hence the name Rapid Eye Movement. This stage occurs around 90 minutes after you fall asleep. 

What happens when we don't sleep?

Although we have these mechanisms in our body to improve sleep and create a balanced cycle, so many people still struggle with getting into a good sleep schedule and getting quality sleep. Some factors that cause a lack of hours of sleep are because of an irregular sleep schedule, poor lifestyle habits, stress or anxiety, depression, or actual sleep disorders such as insomnia.

According to American Sleep Apnea Association, 50-70 million Americans are affected by sleep-related problems, leading to 25% of American adults reporting insufficient sleep on at least half of the days of their month. Poor sleep issues can lead to things like:

  • Daytime Fatigue
  • Trouble Thinking and Concentrating
  • Increase in stress and irritability
  • Anxiety 
  • Depression
  • Weakened Immune System (i.e. getting sick more often)
  • Digestive Issues

Research shows that a lack of quality sleep, which according to most doctors would be at least 7 hours of sleep for people ages 18 and older, can further cause a number of conditions and diseases. Some of these being:

Although sleep is so crucial for every human function, it seems almost common to hear someone is struggling with it. Instead of promoting poor sleep habits and schedules, social media and others should be promoting healthy sleep and balanced schedules. 

If you are 18 or older and struggling with getting enough hours of sleep, don’t fear! We have an article made just for you on all the best tips for how to sleep better from investing in better quality bedding to avoiding late meals. 

If you are struggling with getting enough hours of sleep for prolonged periods of time, make sure to reach out to a trusted doctor to make sure all is right in that brain and body of yours. Sleep is essential, so don’t ignore it!

Why Doctors Recommend 7-9 Hours of Sleep Each Night I Mirra Skincare

Written by Bella Knuth


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  1. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Understanding-Sleep
  2. https://www.sleepapnea.org/
  3. https://www.nhlbi.nih.gov/health-topics/sleep-deprivation-and-deficiency
  4. https://www.sleepfoundation.org/how-sleep-works/why-do-we-need-sleep
  5. https://www.parsleyhealth.com/blog/healthy-sleep-habits/

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