Adam’s Journal
Here’s a question from an Oklahoma Medical Research Foundation colleague:
My wife and I have recently begun tracking our sleep; I use an Oura Ring and she uses a Garmin watch. The devices not only tell us how long we’ve slept but they also rate the quality of our sleep, tracking how much time we’ve spent in different types of sleep.
What are the different types of sleep, and why are they important?
Tony Thornton
Dr. Scofield Prescribes
Sleep generally falls into two categories: Rapid-eye movement (REM) and non-REM sleep.
Not surprisingly, both types help the body restore itself. More surprising, though, is how little we truly understand about why we need sleep and how it functions to repair and recharge our minds and bodies.
That said, I can provide a brief overview of what we do know. To do so, let’s invert the order of things a bit and start with REM sleep.
REM sleep is named for the ways in which our eyes dart around beneath our closed eyelids during this phase of slumber. It’s in this stage that we dream.
For a time, experts believed that REM sleep provided the most benefit, enabling our minds to finish processing experiences, thoughts and memories from our waking lives. Sleep researchers still believe REM sleep is vital, but they now see non-REM sleep as at least an equal partner in more far-reaching restorative processes.
Non-REM sleep – during which, as you’ve no doubt guessed, our eyes remain still – begins when we start to nod off. It starts with its lightest stage, when we are transitioning from waking life to sleep.
From there, it moves to deeper phases of non-REM sleep. Experts now believe that it is in its deepest stage, called Stage 3 or slow-wave sleep, that the body does most of its work repairing itself. When you get adequate amounts of slow-wave sleep, you wake feeling refreshed.
We don’t stay in any of these stages for prolonged periods of time, and we continuously transition from one to another. Typically, a single sleep cycle, during which we move through all of these phases (and some more than once), takes from 90 to 110 minutes. For adequate sleep, we should get through three or four full cycles in a night.
Monitoring your sleep can provide you with a good snapshot of your sleep habits. We’re still learning to parse the data, but in the meantime, one number stands out from all the others. While we may not fully understand sleep, researchers have consistently found that getting at least seven hours a night improves outcomes across a broad spectrum of health conditions.
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Dr. Hal Scofield is a physician-scientist at the Oklahoma Medical Research Foundation, and he also serves as Associate Chief of Staff for Research at the Oklahoma City VA Medical Center. Adam Cohen is OMRF’s senior vice president and general counsel. Send your health questions to contact@omrf.org.
