What is Deep Sleep and How Much of it Do You Really Need?
We know sleep is important, so why aren’t we getting enough?
I frequently ask myself this question because I’m notorious for not sleeping enough. It takes me an hour or so to actually fall asleep, and when I do pass out it’s only for a few (blissful) hours. I tend to over-caffeinate in the mornings and use that fuel to power through the day, and when I get home I start the process all over again. Working at the sleep space has made me hyper-aware of just how poor my sleep habits really are.
I recently purchased a new sleep app that monitors your sleep activity as well as your sleep environment, and the first night I got an interesting result.
I only got 2 hours of deep sleep.
Sleep is arguably one of the most important things we do for our bodies. Healthy sleep habits have tons of health benefits and sleep deficiency is linked to an increased risk of heart disease, kidney disease, high blood pressure, diabetes, and stroke.
Am I at risk? Is 2 hours of deep sleep enough?
Let’s begin by looking at the stages of sleep. What happens when we get a little shut-eye?
The stages of sleep
According to the Sleep Foundation, our sleep cycles follow a pattern of alternating rapid eye movement (REM) and non-rapid eye movement (NREM) sleep each night in a cycle that repeats itself about every 90 minutes. The cycle is broken down as follows.
NREM- 75% of the night
- Stage 1: The relaxed state before you nod off for the night. You can be awakened easily here. Twitching is common.
- Stage 2: Onset of sleep where you start to become disengaged from your surroundings and your body temperature drops.
- Stages 3: The deepest and most restorative sleep. It’s difficult to wake someone during these stages. People who are awakened during deep sleep do not adjust immediately and feel groggy or disoriented.
REM- 25% of the night
- After deep sleep, we slip back into stage 2 before entering REM sleep. We spend almost 50% of our total sleep time in stage 2, about 20% in REM, and the remaining 30% in other stages.
Why is deep sleep important?
Deep sleep is an important part of our nightly sleep cycle where our bodies repair themselves and build energy up for the next day. It’s where the release of growth hormones occurs in children and young adults, helping aid in the body’s maturation process. Deep sleep is also where tissue repair occurs, and where your body detoxifies itself.
“Many of the body’s cells also show increased production and reduced breakdown of proteins during deep sleep. Since proteins are the building blocks needed for cell growth and for repair of damage from factors like stress and ultraviolet rays, deep sleep may truly be “beauty sleep.” Activity in parts of the brain that control emotions, decision-making processes, and social interactions is drastically reduced during deep sleep, suggesting that this type of sleep may help people maintain optimal emotional and social functioning while they are awake.” (Sleep Association)
How much deep sleep do we need?
As we get older we spend less time in deep sleep. Why? One thought is because deep sleep is where growth hormones are released — it makes sense that we spend less time there as we age. The time we do spend in deep sleep is important in helping repair our bodies and gather energy for the next day. Who doesn’t like feeling rejuvenated after great sleep?
Was I crazy to infer that I needed more deep sleep? Not really. After all, who doesn’t like feeling rejuvenated after great sleep? But with the understanding that I’ll never be 15 again, I’ve learned that I don’t need more than 2 hours of deep sleep each night. The next time you pick up your sleep tracker to review your latest sleep statistics, fear not! You’re probably right on track. Some sleep trackers are limited in how much they can really analyze from our sleep.