Sleep: it doesn’t matter how much, but when
If you’re someone who didn’t sleep very well last night for whatever reason, you might be feeling a little jaded as you read this. This is understandable. You may be thinking that simply getting a so-called ‘eight hours’ sleep for the next few nights can restore balance.
This is true up to a point. You’ll learn more about why I say ‘to some extent’ in a moment.
However, it can also be someone who did you get your eight hours last night, and the night before, and the night before, but for some reason you feel like you’re not working on all cylinders. This is also understandable, and you are about to find out why.
Not all sleep is the same
We may think that all dreams are the same. But is not. The quality of our sleep varies from one part of the night to another. Our bodies have a natural rhythm, and that rhythm is thousands of years old. is called a circadian rhythm.
It is the rhythm of nature, and one that animals instinctively live by. As human beings, we are essentially animals and designed to live according to this natural rhythmic cycle.
That cycle can be seen in the passing of the day and the passing of the seasons. We have the dawn of the day (Spring) where we woke up. Then we move on to the main part of our day (summer) when we are more adapted to work. This is followed by relaxing towards the end of the day (fall) and finally sleeping at night (winter).
Therefore, we are naturally designed to wake up with the sunrise and sleep when the sun goes down. When we adjust our lifestyle to accommodate this natural rhythm, we get better quality sleep.
Our natural sleep cycles
Similar to this natural rhythmic cycle, our sleep pattern also has a natural cycle. When we sleep we oscillate between deep regenerative sleep (where the body repairs itself) to the slightly lighter REM (Rapid Eye Movement) sleep state in which we dream.
These sleep cycles last around 90 minutes each. So if he finds that he’s getting eight hours of sleep and still feels tired when he wakes up, he’s probably setting his alarm clock to wake him up in the middle of a sleep cycle instead of at the end.
For example, if you went to bed at 11 pm and woke up at 8 am, you would have slept for nine hours and gone through six complete sleep cycles. These would be:
Cycle 1. 23:00-00:30
Round 2. 12:30 to 2:00
Round 3. 2:00 am-3:30 am
Round 4. 3.30 am-5.00 am
Round 5. 5:00 am to 6:30 am
Round 6. 6:30 am to 8:00 am
After sleeping from 11:00 p.m. to 8:00 a.m., you’ll probably feel pretty refreshed when you wake up.
However, if you set your alarm to wake you at 7 am, you will have slept for eight hours, but you will have woken up during a 90-minute sleep cycle (between 6:30 and 8:00). Therefore, you may not feel as rested upon waking as if you had gotten up at 8:00 a.m.
Repair and rejuvenation
In addition to these shorter 90-minute cycles, according to our circadian rhythm, the body regenerates and rejuvenates the most significantly between 10 p.m. and 2 a.m.
So you might go to bed at, say, 1 a.m. and sleep until 9 a.m. to get your eight hours, but you’re losing three vital hours of body repair each night. And if you work in shift patterns, especially the night shift, you may be throwing off your circadian rhythm entirely, denying yourself the chance to properly repair your body during sleep.
The 3 best sleep tips
So, for the best chance of improving your performance, productivity, and outcomes later in life, consider the following three tips:
1. Adapt your lifestyle to your natural circadian rhythm and go to bed at 22:00
2. Make sure you get eight or more hours of sleep a night
3. Try not to wake up to an alarm clock. If necessary, set it to wake up at the end of a 90-minute sleep cycle instead of in the middle.