Sleep Is Critical for Brain Detoxification, Groundbreaking Research
Finds
October 31, 2013
Story at-a-glance
Sleep is deeply interconnected with your health in a myriad
of ways. For example, previous research has found that sleep
deprivation has the same effect on your immune system as
physical stress or illness
Recent research shows that your brain has a unique waste
management system, similar to the lymphatic system in your
body. This system, dubbed the glymphatic system, is
activated during sleep
By pumping cerebral spinal fluid through your brain’s
tissues, the glymphatic system flushes the waste from your
brain back into your body’s circulatory system and into your
liver, where it’s ultimately eliminated
During sleep, your brain cells also shrink by about 60
percent, which allows for more efficient waste removal
Amyloid-beta, for example—proteins that form the notorious
plaque found in the brains of Alzheimer’s patients—is
removed in significantly greater quantities during sleep
By Dr. Mercola
Scientists have long tried to tease out the purpose of sleep,
and countless studies have concluded that sleep is deeply
interconnected with your health in a myriad of ways. As just one
example, previous research has found that sleep deprivation has
the same effect on your immune system as physical stress or
illness.1
Quite simply, even if you do everything else right, if you
don’t sleep enough, your health and well-being will still
suffer. You may even die prematurely, should poor sleep plague
you long-term.
Now, researchers at the University of Rochester Medical
Center (URMC) Center for Translational Neuromedicine believe
they may have discovered yet another clue as to why sleep is
mandatory for good health—especially brain health.
Their report, published in the journal Science,2
reveals that your brain has a unique method of removing toxic
waste through what’s been dubbed the glymphatic system.3,
4,
5,
6,
7
The clincher is that this system ramps up its activity
during sleep, thereby allowing your brain to clear out
toxins, including harmful proteins linked to brain disorders
such as Alzheimer’s for example.
What’s more, they discovered that your brain cells actually
shrink by about 60 percent during sleep, which allows for more
efficient waste removal. According to lead author Maiken
Nedergaard, M.D., D.M.Sc., featured in the video above:
“This study shows that the brain has different
functional states when asleep and when awake. In fact, the
restorative nature of sleep appears to be the result of the
active clearance of the by-products of neural activity that
accumulate during wakefulness.”
What Is the Glymphatic System?
In your body, the lymphatic system is the system responsible
for eliminating cellular waste products. However, the lymphatic
system does not include your brain. The reason for this is that
your brain is a closed system, protected by the blood-brain
barrier, which controls what can go through and what cannot.
In a previous animal study,8
Dr. Nedergaard showed that the brain actually has its own
unique waste disposal system, similar to that of the lymphatic
system. This system, called the glymphatic system, “piggybacks”
on the blood vessels in your brain. The “g” in glymphatic is a
nod to “glial cells”—the brain cells that manage this system.
By pumping cerebral spinal fluid through your brain’s
tissues, the glymphatic system flushes the waste, from your
brain, back into your body’s circulatory system. From there, the
waste eventually reaches your liver, where it’s ultimately
eliminated.
During sleep, the glymphatic system becomes 10 times more
active than during wakefulness. Simultaneously, your brain cells
are reduced in size by about 60 percent.
This creates more space in-between the cells, giving the
cerebrospinal fluid more space to flush out the debris.
Amyloid-beta, for example—proteins that form the notorious
plaque found in the brains of Alzheimer’s patients—is removed in
significantly greater quantities during sleep. As stated by
Time Magazine:9
“The findings raise interesting questions about how
sleep may affect the progression of Alzheimer’s or other
neurogenerative disorders, but they also provide a strong
warning for anybody who skips sleep. The short version:
don’t.”
“The brain only has limited energy at its disposal
and it appears that it must choose between two different
functional states — awake and aware or asleep and cleaning
up. You can think of it like having a house party. You can
either entertain the guests or clean up the house, but you
can’t really do both at the same time.
...These findings have significant implications for
treating ‘dirty brain’ disease like Alzheimer’s.
Understanding precisely how and when the brain activates the
glymphatic system and clears waste is a critical first step
in efforts to potentially modulate this system and make it
work more efficiently.”
How Sleep Influences Your Physical Health
Sleep is usually one of the first things people
sacrifice when the going gets tough, and this could be a
critical mistake. First of all, significant memory impairment
can occur after a single night of poor sleep—meaning sleeping
only 4 to 6 hours. It also has a detrimental impact on your
ability to think clearly the next day, and decreases your
problem solving ability.
But foggy-headedness and forgetfulness are the least of your
worries should you ignore your poor sleeping habits. Aside from
impacting your immune function as briefly mentioned earlier,
poor sleep is now known to have multi-varied detrimental effects
on your health, courtesy of your circadian system, which
"drives" the rhythms of biological activity at the cellular
level. Disruptions to this biological clock tend to cascade
outward throughout your entire body. For example,
interrupted or impaired sleep can:
Harm your brain by halting new cell production.
Sleep deprivation can increase levels of corticosterone
(a stress hormone), resulting in fewer new brain cells
being created in your hippocampus.
Impair your ability to lose excess pounds or maintain
your ideal weight. This is likely the effect of altered
metabolism, because when you’re sleep deprived, leptin
(the hormone that signals satiety) falls, while ghrelin
(which signals hunger) rises.
Contribute to a
pre-diabetic state, making you feel hungry even if
you've already eaten, which can wreak havoc on your
weight.
Accelerate tumor growth, primarily due to disrupted
melatonin production. Melatonin inhibits the
proliferation of a wide range of cancer cell types, as
well as triggering cancer cell apoptosis (self
destruction). The hormone also interferes with the new
blood supply tumors require for their rapid growth
(angiogenesis)
Furthermore, lack of sleep can further exacerbate chronic
diseases such as:
Parkinson's
Alzheimer's
Multiple Sclerosis (MS)
Gastrointestinal tract disorders
Kidney disease
Behavioral problems in children
Why You Shouldn’t Reach For a Sleeping Pill When You Can’t
Sleep...
Chronic lack of sleep has a cumulative effect when
it comes to disrupting your health, so you can’t skimp on sleep
on weekdays, thinking you’ll “catch up” over the weekend. You
need consistency. Generally speaking, adults need between six
and eight hours of sleep every night. There are plenty of
exceptions though. Some people might need as little as five
hours a night, while others cannot function optimally unless
they get nine or 10 hours.
My strong recommendation and advice is quite simply to
listen to your body. If you feel tired when you wake up,
you probably need more sleep. Frequent yawning throughout the
day is another dead giveaway that you need more shut-eye.
Personally, I find that when I am reading during the day, if my
eyes close and I tend to doze off, I know I did not get enough
sleep the night before. However, above all, should insomnia
strike, don’t make the mistake of reaching for a sleeping pill.
Not only do sleeping pills not address any of the underlying
causes of insomnia, researchers have repeatedly shown that
sleeping pills don’t work, but your brain is being
tricked into thinking they do... One analysis found that,
on average, sleeping pills help people fall asleep approximately
10 minutes sooner, and increase total sleep time by a mere 15-20
minutes. They also discovered that while most sleeping pills
caused poor, fragmented sleep, they induced amnesia, so
upon waking, the participants could not recall how poorly they’d
actually slept!
In terms of health consequences, this could end up being
worse than not sleeping and being aware of that fact. At least
then you’d be encouraged to find and address the root cause of
your sleeplessness. Besides not working as advertised,
sleeping pills have also been linked to significant adverse
health effects, including a nearly four-fold increase in the
risk of death, and a 35 percent increased risk of cancer.
How to Optimize Your Sleep
Below are half a dozen of my top guidelines for promoting
good sleep. For a comprehensive sleep guide, please see my
article "33
Secrets to a Good Night's Sleep."
Avoid watching TV or using your computer at
night—or at least about an hour or so before going
to bed—as these technologies can have a significantly
detrimental impact on your sleep. TV and computer screens
emit blue light; nearly identical to the light you're
exposed to outdoors during the day. This tricks your brain
into thinking it's still daytime, thereby shutting down
melatonin secretion.
Under normal circumstances, your brain starts secreting
melatonin between 9 or 10 pm, which makes you sleepy. When
this natural secretion cycle is disrupted, due to excessive
light exposure after sunset, insomnia can ensue.
Sleep in complete darkness, or as close to it as
possible. Even the slightest bit of light in the
room can disrupt your internal clock and your pineal gland's
production of melatonin and serotonin. So close your bedroom
door, and get rid of night-lights. Refrain from turning on
any light at all during the night, even when getting up to
go to the bathroom. Cover up your clock radio.
Make sure to cover your windows—I recommend using
blackout shades or drapes.
Keep the temperature in your bedroom no higher
than 70 degrees F. Many people keep their homes and
particularly their upstairs bedrooms too warm. Studies show
that the optimal
room temperature for sleep is between 60 to 68 degrees.
Keeping your room cooler or hotter can lead to restless
sleep. This is because when you sleep, your body's internal
temperature drops to its lowest level, generally about four
hours after you fall asleep. Scientists believe a cooler
bedroom may therefore be most conducive to sleep, since it
mimics your body's natural temperature drop.
Take a hot bath 90 to 120 minutes before bedtime.
This increases your core body temperature, and when you get
out of the bath it abruptly drops, signaling your body that
you are ready for sleep.
Check your bedroom for electro-magnetic fields (EMFs). These
can disrupt your pineal gland and the production of
melatonin and serotonin, and may have other negative effects
as well. To do this, you need a gauss meter. You can find
various models online, starting around $50 to $200. Some
experts even recommend pulling your circuit breaker before
bed to shut down all power in your house.
Move alarm clocks and other electrical devices
away from your bed. If these devices must be used,
keep them as far away from your bed as possible, preferably
at least three feet. This serves at least two functions.
First, it can be stressful to see the time when you can't
fall asleep, or wake up in the middle of the night.
Secondly, the glow from a clock radio can be enough to
suppress melatonin production and interfere with your sleep.
Cell phones, cordless phones and their charging stations
should ideally be kept three rooms away from your bedroom to
prevent harmful EMFs.
Sleeping Well Is Part of a Healthy Lifestyle Plan
There's convincing evidence showing that if you do not sleep
enough, you're really jeopardizing your health. Everybody loses
sleep here and there, and your body can adjust for temporary
shortcomings. But if you develop a chronic pattern of sleeping
less than five or six hours a night, then you're increasing your
risk of a number of health conditions, including weakening your
immune system and increasing your risk of degenerative brain
disorders. If you’re feeling anxious or restless, try using the
Emotional Freedom Techniques (EFT), which can help you address
any emotional issues that might keep you tossing and turning at
night.
For even more helpful guidance on how to improve your sleep,
please review my
33 Secrets to
a Good Night's Sleep. If you're even slightly sleep
deprived, I encourage you to implement some of these tips
tonight, as high-quality sleep is one of the most important
factors in your health and quality of life.