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."
According to Dr. Nedergaard:10
"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:
Increase your risk of heart disease.11 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) Contribute to premature aging by interfering with your growth hormone production, normally released by your pituitary gland during deep sleep (and during certain types of exercise, such as high intensity interval training). Raise your blood pressure. Increase your risk of dying from any cause.
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.