NREM Stage 1
When you enter sleep mode, your body begins to transition from wakefulness to sleep. This happens as soon you lie down on your bed, where this state usually lasts from 5 to 10 minutes. You will tend to lose awareness of your surroundings and time as you fall deeper into this stage.
During this stage, your body:
- Decrease in body temperature
- Release of melatonin (the sleep-inducing hormone)
- Your brain slows down
- Your heartbeat and breathing also slows
NREM Stage 2
You will spend 50% of your sleep cycle in this phase which lasts 20 minutes.
- You are less aware of your surroundings
- Your body temperature drops, and your eyes droop
- Your heartbeat and breathing starts to regulate
This is also the stage where your brain consolidates the information you learned throughout the day.
NREM Stage 3
This is called the delta stage, where your brain waves become slower as you enter deep sleep.
Getting enough deep sleep allows you to feel refreshed the next day.
- Your muscles will start to relax
- Your blood pressure drops
- Your breathing slows
- You will progress into your deepest sleep
REM sleep
REM sleep is the fourth stage in your sleep cycle. In this stage, your body is temporarily paralyzed, but your mind is still aroused with mental activities, like when you are awake.
REM sleep happens after 90 minutes after falling asleep.
- Your brain lights up with activity
- Your body is relaxed
- Your breathing is faster
- Your eyes move rapidly
- You dream
Lions are morning hunters, and people who are the Lion chronotype are the early risers of the world. Lions are optimistic, naturally disciplined (including their sleep routines), practical, and goal-oriented. Lions are generally good sleepers with a medium sleep drive. It’s rare to find a Lion who struggles much to stick to a regular, early bedtime.
Lions have a natural tendency for routine and moderation in their daily habits, and this shows in their overall health picture: Studies show that morning types with early bedtimes have a lower risk for cardiovascular disease, less obesity, and may have lower risks for mental health disorders, including depression, anxiety, and others. Lions leap into their days full of energy; the morning and early afternoon are when Lions are at their most productive.
About 15-20 percent of the general adult population are Lions.
Bears are all-day hunters, and Bear chronotypes are go-with-the-flow types with middle-of-the-road sleep-wake preferences. Of the four chronotypes, Bears adhere most closely to a solar schedule. Bears are most alert and productive during the middle of the day, from late morning through early afternoon.
Bears are easygoing and social, fun-loving team players. They have a high sleep drive and tend to sleep deeply. But many Bears carry a sleep debt—they don’t get enough sleep to meet their needs. Bears are prone to inconsistency in their sleep routines. They often under-sleep during the workweek and sleep extra on the weekend to compensate for their insufficient rest. Inconsistent sleep habits can put the Bear circadian clock chronically out of sync. Bears are the most common chronotype—about 50 percent of the adult population are Bears. Because it’s the most common chronotype, Bear time has a dominant influence over our broader social time. Six o’clock is the standard dinner hour because that’s when Bears are ready for their evening meal.
Wolves are nighttime hunters, and the Wolf chronotype has a strong preference for evenings. Wolves are the people who drag themselves out of bed before 9am and don’t start feeling really tired until midnight or so. Wolves are creative, impulsive, and emotionally intense. They love to seek out new experiences and are natural risk-takers. Wolves have a medium sleep drive, with productivity peaks in the late morning and again in the late evening. Because of their strong preference for evening hours, Wolves often struggle with living according to the schedule society demands of them. Things like work and school get going too early, and social fun ends too soon. Wolves typically perform at their best with around seven hours of sleep. Getting that much sleep can be challenging for Wolves because their biological rhythm is so at odds with society’s timetable for daily life. About 15-20 percent of the population are Wolves.
The dolphins of the mammalian world are uni-hemispheric sleepers. That means they sleep with one-half of their brain at a time, with the other half awake and active. That’s a pitch-perfect analogy for this fourth chronotype of restless, light sleepers. Dolphins are “wired and tired” types—chronically tired during the day and wired with restless, nervous energy at night. Dolphins are light and restless sleepers with a low sleep drive, who tend to wake frequently during the night. Their minds are active in the evening, with often racing thoughts, and they feel physically keyed up. There are biological reasons for Dolphins’ nighttime restlessness and agitation. It turns out that Dolphins have circadian biology that is turned upside-down. In contrast to other chronotypes, Dolphins’ brain activity increases at night in areas of the brain that promote alertness. And also, unlike other chronotypes, Dolphins’ blood pressure and cortisol levels rise in the evening, which leaves them in a state of physiological arousal at bedtime. In come morning, when other chronotypes are experiencing elevations to blood pressure and cortisol that are fueling their morning alertness, Dolphins’ levels are plummeting. Personality-wise, Dolphins are highly intelligent, cautious, detail-oriented (perfectionism is a common Dolphin trait), and often anxious. As I’ve said, about 10 percent of the population are Dolphins.
What to do: Knowing what types of your body best functions will allow you to use your energy productively.