When we say "sleep architecture", we're not talking about Frank Lloyd Wright drafting in his sleep, but rather, what does a typical night of sleep look like? What is a sleep cycle? How about sleep phases?
We'll try to answer these questions here.
First, let's think about what sleep looks like over the course of the night by considering sleep depth: how easily you might be woken up (or how close are you to being awake) during a good night of sleep.
Does the graph below lead you to think: "That's what a good night of sleep looks like"? If so...
...you'd be wrong. But you wouldn't be alone (I've asked some very smart folks to draw their best guess and this is how it usually comes out).
Before the advent of sleep science, this was how people thought we slept each night
(with, perhaps, the exception of our astute friend, Shakespeare
A more accurate picture of a night of sleep is this:
Notice how there's lots of deeper seep at the beginning (that's where you'll find most of the aptly named "Deep sleep"), but there are also cycles of sleep. These sleep cycles occur 3 to 6 times each night and they generally last about 90-110 minutes each.
Here at Zeo, we generally talk about four sleep phases. While it's a bit of a cheat to include Wake as sleep, it does play a role as one of the phases.
Here's a quick run through of all four:
- Wake: You start in bed awake and then fall asleep until the morning, right? Not quite. Sleep cycles get lighter several times over the course of the night, and it's not unusual to wake up at the end of any given sleep cycle. In fact waking up a few times during the night is actually okay-- it's how the human body (and brain) was built.
- Light Sleep: Making up about 50-60% of the night, a night of sleep usually starts in Light Sleep. Light sleep can also usually be found between phases of REM and Deep Sleep. It's uncommon to go move between REM and Deep Sleep without passing through Light Sleep.
- Deep Sleep: Making up around 10-15% of the night, Deep Sleep is the deepest sleep phase and shows up mostly in the first third of the night. When the body comes out of Deep sleep, it usually goes back to light sleep before heading into REM.
- REM Sleep: Making up about 20-25% of the night, REM Sleep usually shows up at the end of each sleep cycle. It's more common later in the night, especially during the early morning hours. It's also pretty common to wake up around this part of the sleep cycle.
Check out this pretty typical graph of of my own sleep. Note each of the phases and the overall time as I cycle through them:
Remember that sleep depth chart, above? I made that by averaging over 300 of my own sleep graphs very much like this one.
Being a Sleep Architect
The short of it is that everyone's sleep is different, but as we've seen, there are common characteristics that everyone shares. I'll explore more of the details of sleep architecture in the future, but for now, we want to know:
What what does your sleep architecture generally look like?
Comment below, post your data to Facebook, or send us a TwitPic; we're interested to see what you share!