Why We Sleep: 8 Reasons to Get 8 Hours

“Somewhere between infancy and even childhood now, we abandoned the notion that sufficient sleep is necessary.” – Matt Walker, Principal Investigator at UC Berkeley’s Sleep and Neuroimaging Lab

How do you decide how much sleep you need? Is it really a decision, or is it more of a function of what your lifestyle allows? What if you can’t fall asleep or stay asleep? How does the amount you sleep and the quality really affect your health and performance? I plan to address these questions in my new series, Why We Sleep.

why we sleep, how much is enough sleep?

I know I did a two-part series already called Sleep Better a while back, but I promise there’s a ton of new and intriguing information that isn’t repeated from that series, so stick with me; you might be surprised at what you find out. And my hope is that what you learn will motivate you to get the sleep you need as consistently as you possibly can!

In this series, I will cover:

  1. Prioritizing Sleep
  2. How Much Sleep is Enough
  3. The Health Risks of Not Sleeping Enough (8 Reasons to get 8 Hours)
  4. What Happens When We Sleep
  5. Misconceptions About Sleep
  6. 10 Tips for Good Sleep Hygiene

We’ll cover the first three on this list today and start you off with one tip to work on for the week.

Prioritizing Sleep

Sleep is one of those things we all need but don’t always prioritize properly. Lately I’ve noticed myself getting caught up in post-work activities and then looking up at the clock to realize it’s 10:45pm and I haven’t started doing anything to prepare for sleep. My usual routine is to be in bed by 10:30, so this new (bad) habit of mine can cut into my sleep schedule by as much as an hour — and I can definitely feel it when I wake up in the morning. 

Understanding the role sleep plays in our health and wellbeing can help us understand why it’s so important to prioritize sleep, whether it’s in the form of greater discipline around a sleep routine (as is the case for me) or in the form of seeking help (as is the case for those with sleep pathologies like insomnia or sleep apnea).

After having a long conversation with a friend late into the evening on the topic of sleep challenges, I decided to revisit an episode of the Inquiring Minds podcast, Why Did We Evolve to Sleep? When this episode first aired, I sent it out to everyone I know who has trouble sleeping, and sadly, it was a pretty long list. According to Matt Walker, the expert interviewed in this episode, over 70 MILLION Americans have trouble sleeping. That’s completely insane to me, but just based on what I know of the people in my life, I believe it’s an accurate estimate. 

How Much Sleep is “Enough”?

“Humans are the only organism on earth that intentionally deprives ourselves of sleep for no reason.” – Matt Walker

I can honestly say that I’ve never subscribed to the colloquialism, “I’ll sleep when I’m dead.” I LOVE sleeping. In fact, I’m a pretty terrible grouch when I don’t get enough sleep (I’d go as far as to say I’m relatively useless). I never believe people who say, “I don’t need to sleep that much. Six hours is enough,” because I can’t personally fathom doing that for more than one night in a row without completely losing my mind. But that’s just my personal take on the topic.

What does the science say? 

To best answer that question, we first have to understanding that our brains need a minimum amount of time to achieve both types of sleep (REM and non-REM) and all the stages of sleep (of which there are 4). And we go through these types and stages in cycles throughout the night. Based on what’s accomplished in these distinct components of sleep, research has confirmed what we’ve been told for years — we (adults) need about eight hours of sleep in each 24 hour cycle to stay healthy and function properly (source 1, source 2, source 3). If we get less than 7 hours of sleep, performance and health impairments become scientifically measurable and significant a lot more quickly that you might think. Our ability to bounce back from sleep debt is surprisingly limited.

In fact, consistently short-sleeping ourselves has been linked to a host of health problems, including a shocking number of chronic diseases. 

Sleeping Enough is Vitally Important for Good Health

why we sleep, how much is enough sleep?

photo in this image taken by Mike Durkin, color balance altered, sourced through Creative Commons

Avoiding disease and enhancing good health all seem like pretty strong motivations to find a way to prioritize sleep, but sometimes the prospect of long-term health problems isn’t quite motivation enough to change behavior (otherwise we’d all be skipping dessert and eating a lot more kale!). Sometimes we need more immediate benefit to take action. What if I told you that measurable impairments in brain function can take place in as little as one poor night of sleep? Don’t believe me? It turns out that sleep-deprived folks have a very poor ability to recognize the impairments they’re experiencing while they’re sleep deprived. It’s a lot like a drunk driver when you think about it — you’ve had a few drinks and you think you’re fine, but compared to your sober self, you’re definitely impaired. If you think you’re performing at your best on 5 or 6 hours of sleep per night, chances are your perspective is a bit skewed. 

We’ll talk a bit more about sleep deprivation, what happens when we sleep, and which processes take place when we’re asleep (and only when we’re asleep) in next week’s installment, but in the meantime I don’t want to leave you empty-handed. Let’s get you started on the journey to deep, restorative sleep!

Get some ZZs

The best way to ensure good quality sleep (getting to sleep, staying asleep, and feeling rested upon waking) is to start good habits and create a good sleep environment. Practicing good sleep hygiene and listening to the signals your body is giving you that it’s time to hit the hay take time to learn and implement consistently. By the end of this series, you’ll have a solid list of 10 tips for excellent sleep hygiene, but for today I’m just going to share the first one to get you started. Incremental change is the way to go, so by the time you get to next Tuesday’s post, you’ll be ready for tip #2!

Sleep Tip

why we sleep, how much is enough sleep? how much sleep do we need?

Sources for information on health risks in infographic above:

1. Stroke
2. Cardiovascular disease
3. Diabetes (Inquiring Minds Podcast linked at top of post)
4. Anxiety
5. Depression
6. Immune Function (Inquiring Minds Podcast linked at top of post)
7. Cancer 
8. Alzheimer’s Disease

FTC DISCLOSURE: This post contains an affiliate link, which means I may receive monetary compensation for my endorsement, recommendation, testimonial and/or link to any products or services from this blog. I only link to products that I USE and LOVE. All opinions are my own.


I'm a wellness professional with a Master's in Integrative Health, passionate about spreading health, happiness and personal fulfillment to as many people as possible. I have a professional background in health and wellness, dietary supplements, and nutrition, and embark every day to live a well, balanced, happy life. In being true to myself and what I seek in life, I hope to inspire others to do the same, to cultivate wellbeing in their own lives.

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