1: Dr. Matthew Walker had just finished delivering a public lecture on sleep when a distinguished-looking gentleman dressed in a tweed suit jacket approached the podium.
“As a pianist,” he said, “I have an experience that seems far too frequent to be chance. I will be practicing a particular piece, even late into the evening, and I cannot seem to master it. Often, I make the same mistake at the same place in a particular movement. I go to bed frustrated. But when I wake up the next morning and sit back down at the piano, I can just play perfectly,” Matthew shares in his powerful book Why We Sleep.
The gentlemen’s inquiry intrigued Matthew. He replied it was a fascinating idea, but he knew of no scientific evidence to support the claim.
Ultimately, it sent him on a three-year journey to discover the answer. He and his colleagues eventually ran an experiment taking a large group of right-handed individuals and taught them to to type a number sequence on a keyboard with their left hand, such as 4-1-3-2-4, as quickly and as accurately as possible.
“Like learning a piano scale, subjects practiced the motor skill sequence over and over again, for a total of twelve minutes, taking short breaks throughout,” he writes. Not surprisingly, the participants got better with time.
2: This is where it gets interesting.
The participants were divided into two groups. Half learned the sequence in the morning. They were tested twelve hours later after remaining awake for the rest of the day. The other half learned the sequence in the evening. They were retested the following morning, also after a twelve-hour delay, but one that contained a full eight-hour night of sleep.
“Those who remained awake across the day showed no evidence of a significant improvement in performance,” Matthew writes. “However, fitting with the pianist’s original description, those who were tested after the very same time delay of twelve hours, but that spanned a night of sleep, showed a striking 20 percent jump in performance speed and a near 35 percent improvement in accuracy.”
The surprises don’t stop there. Those participants who learned the sequence early in the day, who showed no improvement that evening, also experienced an identical improvement in performance the following morning after a full night’s sleep.
As it turns out, practice doesn’t make perfect. Practice, with sleep, makes perfect.
3: The amount of sleep we get is a key driver in this equation. “The increases in speed and accuracy, underpinned by efficient automaticity, were directly related to the amount of stage 2 NREM, especially in the last two hours of an eight-hour night of sleep (e.g., from five to seven a.m., should you have fallen asleep at eleven p.m.),” Matthew writes.
There is a steep price to pay by those of us who cut short our sleep.
“Those last two hours of sleep are precisely the window that many of us feel it is okay to cut short to get a jump start on the day,” Matthew notes. “As a result, we miss out of this feast of late-morning sleep spindles.”
Reflection: Am I getting enough sleep? Do I prioritize sleep?
Action: Track my sleep over the next two weeks, using a Fitbit, Oura ring, or by manually tracking.