How much does sleep affect your athletic performance?
Martin Rawls-Meehan explains the science behind getting enough rest.
By Martin Rawls-Meehan June 2012
All images: Pascal Shirley
Think back for a moment to what your life was like before you were introduced to CrossFit.
What did you eat? How did you work out? How did you
measure your fitness from one week to the next?
Good sleep is one of the most
important elements of health
maintenance, as well as
athletic performance
and improvement.
If you’re like most of us, you probably thought about
what you ate a bit. Maybe your diet was based loosely
on some nutritional tips you’d picked up along the way,
but it probably wasn’t based on sound science. The same
probably can be said for how you worked out. You used
the machines that were available and probably picked
up workout tips from friends, coaches, magazines, etc.
Chances are you never did a squat snatch before CrossFit,
nor did you stay away from bread and grains in favor of lean
meat, nuts, seeds and veggies. Now compare your level of
fitness and health now to then. Big difference, right?
CrossFit’s workout methodology is based on science. Like
science, it is continually evolving. Similarly, Paleo nutrition
principles are based on science and an evolutionary
framework. Workout methodology and nutrition are two
essential elements of fitness and general well-being.
When you follow scientifically sound principles that are
consistently tested, proven and refined within a large
community of experimenters, you are going to see strong
results. For many of us, the results have been quite amazing.
Sleep: Another Key to Fitness
How much do you think about how well you sleep?
How important do you think sleep is to your CrossFit
performance? What about your general health?
Stay up too late watching a Real Housewives of Orange County marathon, and it will haunt you during your WOD.
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If you’re like most, you probably don’t think much about
how well you sleep. All know they feel better when they
sleep more, so you probably want to sleep well and are
upset when you don’t sleep as much as you want.
Exercise, nutrition and
sleep make a virtuous circle
comprising the three essential
elements of fitness.
But getting good sleep is more than just sleeping more,
and it does a whole lot more for you than make you feel a
little better during the day. Good sleep is one of the most
important elements of health maintenance, as well as
athletic performance and improvement.
Like the science of nutrition and exercise, sleep science
has been undergoing a revolution over the last few
decades. Researchers are beginning to understand how
sleep impacts our performance over the short term and
long term.
Just how much can sleep impact you as an athlete?
Consider the following:
•
Researchers conducted a study of over 30 years of
National Football League game data and demonstrated
that teams that traveled three time zones to
play night games experienced disrupted sleep and
exercise schedules and were 67 percent more likely
to lose even when the point spread was factored
in (1).
•
Studies have shown that athletes who consistently
get around 10 hours of sleep per night show marked
improvement in strength, speed, agility and reaction
time (2).
•
Athletes who get around 10 hours of sleep
demonstrate significantly better muscle memory for
movements learned the day before (3).
•
People who don’t get enough sleep are more prone
to diabetes, obesity, hypertension and other various
cardiometabolic and endocrine disorders (4).
•
Researchers have shown that just a few days of little
to no sleep impact the body’s insulin sensitivity by
more than 25 percent in normal, healthy people. This
essentially brings them to a pre-diabetic state—the
equivalent of gaining 18 to 30 lb. (4).
•
Military research shows that sleep-deprived soldiers
demonstrate decreased ability in marksmanship,
judgment and overall performance in mental and
physical tasks (5).
•
People who don’t sleep enough are often more
irritable because the brain works differently when
we are sleep deprived (3). An irritable athlete usually
is not a positive athlete. Thus, sleep deprivation can
rob you of the mental edge necessary for success.
To see significant improvements in performance, we have
to train right and eat right. But without enough sleep,
that work is wasted and could even be harmful for a body
so sleep deprived it can’t heal itself. Exercise, nutrition
and sleep make a virtuous circle comprising the three
essential elements of fitness. You can’t achieve your body’s
maximum potential in athletic performance or be at peak
levels of health unless you pay attention and work hard at
all elements.
The good news is that …
there are ways for you to
improve your sleeping habits
and realize your maximum
potential as an athlete.
The good news is that—like nutrition has Paleo and
exercise has CrossFit—there are ways for you to improve
your sleeping habits and realize your maximum potential
as an athlete. But before we get into that, let’s delve a little
deeper into the science behind why sleep is important to
health and athletic performance.
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The Four Stages of Sleep
Important Benefits of Slow-Wave Sleep
Sleep occurs in cycles throughout the night, with each
sleep cycle taking approximately 90 minutes. Our body’s
biological clock controls all of this, and technically the sleep
cycle is one of our many circadian rhythms. There are four
identifiable stages in each sleep cycle; each has a significant
impact on athletic performance and improvement.
•
Stage 1: Lasts for about 20 minutes and is the stage
where the heart rate slows and the body temperature
begins to cool. Brain activity during this time
shows up in “spindles,” which are essentially tightly
packed brain-wave patterns. These spindles have
been linked to muscle memory and internalizing
movements learned during the day (3,6).
•
Stages 2 and 3: Stage 2 is the transition from light
to deep sleep, and Stage 3 is complete deep sleep
where the body produces very slow delta waves.
This stage of sleep is often called “slow-wave sleep,”
or SWS. During this stage, human growth hormone,
or HGH, is released and blood rushes from the brain
to the muscles to initiate recovery and re-energize
your body (3,4). Up to 70 percent of the body’s daily
production of HGH might occur during this state
(7). Additionally, elements of the parasympathetic
nervous system are triggered while the sympathetic
nervous system is suppressed. All this supports
immune function and normal glucose metabolism
during the day (4).
•
Stage 4: Otherwise known as “rapid-eye-movement
sleep,” or REM. This is the stage where we dream.
Our arms and legs are paralyzed, and this is the
only stage of sleep where the body doesn’t actually
move. This stage of sleep is associated with learning
and memory retention, where the hippocampus
transfers and filters the day’s information to the
neocortex (3), kind of like a computer uploading
information and clearing its RAM onto a hard drive.
During the first few cycles, deep-sleep periods are longer
and REM periods are shorter, but after the fourth cycle,
REM periods become much longer and the deep-sleep
phases much shorter.
•
Maximum natural production of HGH: This is a
hormone that the body naturally produces. If you
want to get stronger and faster, then you need your
body to maximize natural production. You only can
do this by getting adequate amounts of deep sleep.
While it is true that most of the HGH released during
the night is released in the first few sleep cycles,
research has shown that sleep deprivation can
throw this off and eliminate the HGH bursts we get
in the first few cycles of sleep (3).
•
Suppression of cortisol production: High levels
of cortisol in the night create insulin resistance in
the morning, and it is linked to cardiometabolic
disorders such as Type 2 diabetes, as well as memory
loss and cognitive impairment (3,7). Additionally, if
you are a Paleo and/or Zone practitioner, it will
significantly throw off your body’s ability to process
glucose throughout the day.
•
Suppression of sympathetic nervous system in
favor of parasympathetic nervous system: The
sympathetic nervous system is what is activated
under stress, whereas the parasympathetic nervous
system is what the body activates to recover and
recuperate (4).
•
Release of prolactin, which has been shown to be
connected to proper immune system function (4).
Insufficient REM sleep has a
negative impact on the brain
as a whole and causes it to
function abnormally.
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Important Benefits of REM Sleep and
Stage 1 Sleep
Spindles are critical to the brain’s ability to transfer learned
muscle movements to permanent memory (3,6).
It is the period where the hippocampus transfers information
to the neocortex, allowing us to recall information,
motor skills and other important information when we wake
up (3). Without enough REM sleep, we can’t remember
and internalize important movements. Therefore, athletes
in sports that require highly skilled movements—like the
snatch, clean and jerk, and muscle-up, where fractions of an
inch are the difference between success and failure—need
enough REM sleep to maintain and improve performance.
Insufficient REM sleep has a negative impact on the brain
as a whole and causes it to function abnormally. As a
consequence, the hippocampus works less and other
parts of the brain, like the amygdala, work more. Because
the amygdala is associated with rage and aggression,
sleep-deprived people often are more irritable and
moody (3). Because a positive attitude is so important to a
sport like CrossFit, athletes simply can’t afford lapses that
will cause them to lose their positive edge.
Steps to Sleeping for Performance
Make a decision here and now that sleep is an integral
part of your training and that you are going to take it as
seriously as exercise and nutrition.
Block out at least nine hours
a day for sleep—ideally 10
hours. You might not actually
sleep that long, but that
should be your goal.
Block out at least nine hours a day for sleep—ideally 10
hours. You might not actually sleep that long, but that
should be your goal. We often fall short of what we set out
to do, so if you set out to do nine, you might only get eight,
which basically is the minimum for an athlete. That said,
“You were up late reading CrossFit Journal articles,
weren’t you?”
everyone has unique sleep needs. If you think you need
nine and half hours a night to perform at a peak level,
then find that out. How do you know if you are sleeping
enough? If you consistently wake up feeling good without
an alarm clock, that is a strong sign you’re close to where
you need to be in terms of sleep.
The Do’s
•
Eat better. Better nutrition helps sleep. In turn,
sleep helps metabolism. It’s a cycle. To maximize
the benefits of nutrition and sleep, you need to do
both well.
•
Give up smoking or any other form of tobacco (3).
•
Perform WODs in the late afternoon or early evening,
finishing the workout before 7:30 p.m., if possible.
Your circadian rhythms prime your body for peak
performance during this time. In contrast, early
morning and late night are the circadian-rhythm
low points for performance. If you do multiple
workouts in a day, try to put the hardest one in the
late afternoon or early evening and avoid doing any
workouts too early or too late in the day.
•
When doing particularly hard workouts during a day
or the course of a week or month, be sure to get
extra sleep during that time to maximize your gains.
•
Keep your room dark, quiet and cool at night. Light,
hot temperatures and noise can disrupt sleep
patterns and cause you to sleep poorly.
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Sleeping like a fit, well-tanned baby.
The Don’ts
•
Avoid caffeine after the early afternoon (3,8). Caffeine
can keep you up and shorten the length of time you
sleep (9).
•
Do not eat a big meal or have alcohol within 3 hours
of going to bed (3,8).
•
Avoid taking long naps during the day. Sometimes
it’s unavoidable, but try to keep them under 30
minutes to avoid throwing off your biological
clock. Taking long naps can have a similar effect
on the body as jet lag. If you need to take a nap
that is longer than 30 minutes, try to get in at least
one full sleep cycle—about 90 minutes—to avoid
feeling groggy.
•
Don’t wake up early to do a workout and keep
yourself from getting enough sleep. You are moving
backward, not forward. The body needs sleep like it
needs water. You wouldn’t deprive yourself of water
so you could work out, right? Of course not; it would
be counterproductive.
•
Do not watch anything on an electronic screen
right before bed. These screens emit blue light,
which essentially inhibits production of melatonin
and prevents sleep. If you need to watch TV, etc.,
before bed, then buy a pair of blue-light-blocking
sunglasses for a few dollars and wear them while
watching. You’ll notice the difference in sleepiness
right away.
Sleep Systems
For a good night’s rest, you need a good sleep system.
Full disclosure: I helped found a company that sells
sleep systems.
You spend one-third of your life in bed, so it’s worth it to
get the right system. Disruption of sleep—be it tossing
and turning or actually waking up—throws off your sleep
patterns and deprives you of the true benefits of sleep.
Many people wake up and toss and turn because they
sleep on an uncomfortable surface that cuts off circulation
to their muscles during the night.
Here’s what I recommend:
•
A mattress made primarily of natural materials.
Synthetics, including urethane and memory foam,
might emit harmful volatile organic compounds, or
VOCs, that create an unhealthy environment around
the bed.
•
A mattress that creates airflow from top to
bottom. Airflow keeps you cool at night. A cool
sleeping environment helps you sleep better and
undisturbed.
•
A mattress with softness/firmness you can
customize.
•
A foundation with head and foot adjustability to
allow for relaxation and a comfortable sleeping
position. Ideally, the foundation would have a
massage feature to help break up lactic-acid build-up
and improve circulation while you are resting.
•
A pillow that is as soft/firm and thick/thin as you like
it to be.
Sleep Well, Train Hard
At this point you probably are worrying you aren’t reaching
your full potential because you’re not sleeping enough.
That’s a good thing because it’s probably true. But keep in
mind that sleeping better isn’t difficult; it just takes some
effort and discipline. Yeah, I know: 10 hours sounds like
a lot of sleep. Trust me, as an athlete you probably need
it if you want to maximize your gains. The good news is
it’s the easiest way to see significant improvements in
performance. So by just following some of the above
tips, you should be well on your way to better health and
better fitness.
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CrossFit is a registered trademark ® of CrossFit, Inc. Feedback to feedback@crossfit.com
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References
1.
Smith R, Guilleminault C, and Efron B. Sports, sleep,
and circadian rhythms: Circadian rhythms and
enhanced athletic performance in the National
Football League. Sleep 20(5): 1-4, 1997.
2.
McCann Kathleen. Ongoing study continues to show
that extra sleep improves athletic performance.
American Academy of Sleep Medicine. June 4,
2008. Available at http://www.aasmnet.org/articles.
aspx?id=954. Accessed May 8, 2012.
3.
Maas J and Robbins R. Sleep for Success: Everything
You Must Know About Sleep But Are Too Tired To Ask.
Bloomington, Ind.: AuthorHouse, 2010. pp. 171-183,
27-31, 58-81.
4.
Van Cauter E and Tasali E. Slow-Wave Sleep: Beyond
Insomnia. Roth T and Dijk DJ, ed. London, England:
Wolters Kluwer Pharma Solutions, 2010. pp. 83-128.
5.
Miller NL, Matsangas P, and Shattuck LG. Performance
Under Stress. Hancock PA and Szalma JL, ed.
Burlington, Vt.: Ashgate Publishing Co., 2008. pp.
231-249.
6.
Tamminen J, Payne JD, Stickgold R, Wamsley EJ,
and Gaskell MG. Sleep spindle activity is associated
with the integration of new memories and existing
knowledge. The Journal of Neuroscience 30(43):
14356–14360, 2010.
7.
Van Cauter E, Leproult R, and Plat L. Age-related
changes in slow wave sleep and REM sleep and
relationship with growth hormone and cortisol
levels in healthy men. The Journal of the American
Medical Association 284(7): 861-868, 2000.
8.
Bauer J. Eat your way to a good night’s sleep.
MSNBC.com. Feb. 5, 2008. Available at http://
today.msnbc.msn.com/id/23003124/ns/todaytoday_
health/t/eat-your-way-good-nights-sleep/.
Accessed May 8, 2012.
9.
Mayo Clinic staff. Caffeine: How much is too much?
MayoClinic.com. March 9, 2011. Available at http://
www.mayoclinic.com/health/caffeine/NU00600.
Accessed May 8, 2012.
F
About the Author
Martin Rawls-Meehan is co-founder of Empire City CrossFit
and a former Division I sprinter at Princeton University. He is
a member of the Specialty Sleep Association and a founding
member of The SSA Green Advisory Board. He holds more than
12 patents for sleep products. In 2003, he helped found Reverie,
a brand of customized sleep systems. Rawls-Meehan can be
reached at martin@reverie.com.
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