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What Is Deep Sleep And How Much Do You Need?

Tara Youngblood


What is deep sleep and how much do i need

“What is deep sleep and how much do I need?” is a combo question I hear all the time from our customers. Since our sleep systems are designed to help you maximize this crucial stage of sleep, it makes sense that it’s a hot topic for us. Defining deep sleep is easy—and we’ll do that in a minute—but how much deep sleep you need is entirely subjective.

For example, it definitely depends on your age since the amount you get will decline as you get older. When you’re 20 years old, approximately 20% of your sleep is deep sleep. But, by the time you’re 80, it might be 5% or less.

This all leads to getting as much as possible while you can. So today we’ll quickly run down what deep sleep is, how much you should try to get each night, and how our products can help.

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What is Deep Sleep?

Deep sleep is the third stage of non-REM sleep. Also known as slow-wave sleep, this is the stage where your brain waves are the slowest as well as your breathing and heart rate. Your body goes through many vital procedures for optimal functioning of the brain. At this time, your body is hard at work! 

There are various ways to describe the stages of sleep, but for the sake of simplifying it we break sleep down.

Stages of Deep Sleep


This first stage is fairly simple to understand: “Bedtime” is when you receive signals that it’s time to hit the hay; your body reaches its highest temperature, triggering your “sleep switch.” Melatonin is released, and your body is primed for sleep. Once you settle in, your heart rate decreases, your muscles relax, and your brain waves abate, preparing you for sleep.

Many people ignore this and get a second wind, but those with sleep issues or full-blown insomnia should obey these bedtime signals, ultimately following their chronotype.

Deep Sleep

The first half of the night is your deep sleep window. During this period, everything drops further: your heart rate, your breathing, your blood pressure, your muscle activity, and your body temperature (and you better believe we’ll come back to that). 

Deep sleep is most dense in the first half of the night, which happens right before our body drops to its lowest point temperature-wise. This stage is also referred to as “delta sleep” in reference to delta brain waves, which are slower and indicate you’ve reached a deeply meditative and dream-free sleep. It’s also important to note that this is the most restorative stage of sleep

REM Sleep

REM sleep happens over the last half of the night, usually about 90 minutes after you fall asleep. Basically, you’re rising out of that “valley” as your core body temperature warms up. What’s interesting about this sleep stage is that some neurons and areas of the brain are as active as they would be if you were awake, while others remain dormant. It’s during REM sleep that you’d be most likely to experience lucid dreams.

How Much Deep Sleep Do I Need?

Now that you have an understanding of the stages, we can discuss how much deep sleep is needed, and it’s fairly straightforward: the ideal amount is two hours. However, how much you get will depend on your age and current sleep needs. According to research by the US Committee on Sleep Medicine and Research, healthy adults spend roughly 13-23% of their sleep in deep sleep.

They also noted a drop in deep sleep over time as we age. This happens due to changes in hormones as the body produces lower levels of growth hormone each year.

How many hours of deep sleep do you need and are you getting enough?  There are the usual telltale signs: waking up feeling tired, tossing and turning during the night, being easily awakened, and even getting up to go to the bathroom. The last one surprises people, but if you’re experiencing true deep sleep a hormone is released that serves as an antidiuretic, ensuring you stay asleep.

Benefits of Deep Sleep

There are plenty of benefits and below are just a few examples that illustrate why it’s so important to get as much as possible on a nightly basis.

  • Increase growth of cell regeneration
  • Increased blood flow to muscles
  • A stronger immune system
  • Energy renewal
  • Development, growth, and repair of tissues and bones
  • Immune system support
  • Boost learning and memory consolidation

Not Enough Deep Sleep

As we know, in general, poor quality of sleep can cause some conditions including obesity, mood disorders, heart disease, and migraines. By a loss of deep sleep increase the chance of the following:

  • High blood pressure
  • Heart attack & stroke
  • Dementia and Alzheimer’s disease
  • Type 2 Diabetes

Why Is Deep Sleep Important?

If you want to read one sentence about the importance of deep sleep, let it be this: it helps your body and mind heal. Deep sleep has restorative power for us physically, including cell regeneration, a strengthened immune system, tissue and bone repair, and more. Ultimately, getting enough deep sleep allows you to renew your energy levels to face each and every day.

It’s obviously associated with cognitive performance, too. Having a sluggish brain is a surefire sign you’re not getting enough. It’s also tied to memory reconciliation; during the day, you don’t organize your memories—this takes place at night while you sleep.

If you think about your memories as files on a desk, getting enough deep sleep allows you to determine what memories are important and which aren’t, effectively “clearing” your desk overnight. This means getting deep sleep has a significant impact on both your short-term and long-term memory (which also helps explain why lack of sleep has been associated with Alzheimer’s disease).

How Does Deep Sleep Affect My Overall Health?

Now that you understand more about deep sleep—that respiration, heartbeat, and eye movements decrease, muscles fall at ease, and those brain waves start to transition you from being awake to being asleep as your core temperature drops—you can probably guess how restorative it can be.

Some people struggle to wake up at all during this stage, but if you’ve been roused from a deep sleep before—by a telephone, a barking pet, or an alarm—you probably felt groggy and confused due to the disruption.

There’s a lot going on during the deep sleep stage, and all of it is beneficial. If you’ve ever had a rough night of tossing and turning, or experienced insomnia, you know it affects cognitive performance, especially for your short- and long-term memory, as well as your brain’s ability to absorb new information. Since glucose metabolism escalates during deep sleep, it strengthens your memory and overall learning capability.

It's a necessary part of our sleep process, but only one factor of a good night's sleep. There are many ways to help promote deep sleep, but the best way is to create more time to sleep each night. 

About Tara Youngblood

Tara Youngblood is ChiliSleep’s co-founder and CEO. An accomplished scientist, author, and speaker, Tara’s unique ideas are revolutionizing the future of sleep health by making sleep easy, approachable, and drug-free.
Learn more about Tara.