The
world is catching on to the value of sleep.
While quotes such as “I’ll sleep when I’m dead” were exclaimed and
touted as a badge of honor, an indication of an individual squeezing the most
out of life, sleep is now more and more valued as a key pillar of health and
wellness.
This
blog series will cover sleep as it’s related to motor learning, injury prevention, and recovery. Today’s focus will be motor learning. Much of the content here is inspired by a
book that I’ve read and re-read multiple times over the past 1.5 years. It’s called, “Why We Sleep: Unlocking thePower of Sleep and Dreams”, authored by Matthew Walker, PhD. I highly recommend the book. It’s a
fascinating read.
How
does sleep help with motor skill acquisition, anything from learning to ride a bike,
play a sport, drive a car?
For
every skill we master, there is a routine associated with the skill that lives
in the brain.
Dr.
Walker’s research demonstrates that after learning or practicing a skill, your
brain will continue to improve the skill routine with a solid night’s
sleep. Thus, practice does not make
perfect, but practice, followed by a night of sleep, makes perfect.
One of
the key studies associated with this discovery involved a group of right-handed
subjects who were asked to learn to type a number sequence on a keyboard. Performance and improvement were tracked over
the course of a training session. Then
subjects were given a 12-hour break, after which they were re-tested on their
performance of the sequence. Half the
subjects learned the sequence in the morning, thus the re-testing period came
12 hours later after being awake during the day. The other half learned the
sequence at the end of the day and were re-tested the following morning after a
full eight hours of sleep. The group
that was re-tested after a night’s sleep
demonstrated a 20% jump in performance speed and a 35% improvement in accuracy
whereas the group that was re-tested after a 12-hour period of being away did
not demonstrate improvement.
Sleep
transfers the motor programs from circuits that operate at the conscious level
of control to brain circuits that operate below the level of consciousness
(subcortical circuitry), embedding the skills as habits.
If
you’ll recall, our nightly sleep cycle is divided into stages and we cycle
between NREM (non-rapid eye movement) and REM (rapid eye movements) stages
throughout the night. Motor skill
enhancement is related to stage 2 NREM, particularly
in the last two hours of an eight-hour night of sleep. Additionally, Walker’s
research found the highest amount of brainwave activity in the areas of the
brain just above the motor cortex, which is indicative of the specificity with
which sleep treats the brain.
Given
the above research, we and our patients should all think twice about cutting
the last two hours of nightly sleep short as we so often do in order to get a
jump start on the day.
Stay
tuned for Part II in two weeks on sleep and injury prevention and recovery.
Kelly Grimes is a physiotherapist with Columbia University Medical Center in New York and an instructor with Movement Links. She is interested in learning how to help herself, her clients, and those she loves reach for better versions themselves in all aspects of life.
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References
1. Walker M. Why We
Sleep: Unlocking the Power of Sleep and Dreams. New York, NY: Scribner;
2015.
2. Walker MP, Brakefield T, Morgan A, Hobson JA, Stickgold
R. Practice with Sleep Makes Perfect: Sleep-Dependent Motor Skill Learning. Neuron. 2002;35:205-211.
3. Kuriyama K, Stickgold R, Walker MP. Sleep-dependent
learning and motor-skill complexity. Sleep
and Memory/Research. 2004;11:705-713.
