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  • A number of studies have linked poor sleep or lack of sleep to an increased risk of Alzheimer’s disease; one reason for this is because your brain’s waste removal system only operates during deep 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, from where it can be eliminated
  • During sleep, the glymphatic system becomes 10 times more active than during wakefulness. Simultaneously, your brain cells shrink by about 60 percent, allowing for greater efficiency of waste removal

Lack of Sleep Promotes Alzheimer’s by Preventing Critical Detoxification

April 02, 2015 | 350,642 views
| Available in EspañolDisponible en Español

By Dr. Mercola

Sleep disturbances are endemic in the US, where nearly 40 percent of adults report unintentionally falling asleep during the day in the past month, and five percent report nodding off while driving.1

Forty-five percent of teens also don't get enough sleep on school nights and 25 percent report falling asleep in class at least once a week.

Lack of sleep has ramifications that go far beyond not feeling fully awake and refreshed during the day. There's a price to pay in terms of health, both short- and long-term.

A number of studies have linked poor sleep or lack of sleep to an increased risk of Alzheimer's for example, and one of the reasons for this has to do with the fact that your brain's waste removal system only operates during deep sleep.

Your Brain Needs Sleep for Waste Removal

There's no cure for Alzheimer's disease, which makes prevention all the more important, and sleeping well appears to be an important part of prevention. Studies2,3 published in 2012 and 2013 revealed that your brain actually has a unique method of removing toxic waste.

This waste-removal system has been dubbed the glymphatic system,4,5,6,7,8 and operates in a way that is similar to your body's lymphatic system, which is 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.

The glymphatic system gets into your brain by "piggybacking" 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.

The clincher is that this system ramps up its activity during sleep, thereby allowing your brain to clear out toxins, including harmful proteins called amyloid-beta, the buildup of which has been linked to Alzheimer's.

During sleep, the glymphatic system becomes 10 times more active than during wakefulness. Simultaneously, your brain cells shrink by about 60 percent, allowing for greater efficiency of waste removal.

During the day, the constant brain activity causes your brain cells to swell in size until they take up just over 85 percent of your brain's volume,9 thereby disallowing effective waste removal during wakefulness.

More recently, researchers discovered10 that the blood-brain barrier naturally tends to become more permeable with age, allowing more toxins to enter.

In conjunction with reduced efficiency of the glymphatic system, damage in both your brain and blood-brain barrier can start to accumulate at an increased pace. This deterioration is thought to play a significant role in the development of Alzheimer's.

Sleep Is Not a Luxury, It's an Essential for Good Health

As noted in a recent issue of Time Magazine:11

"Sleep, the experts are recognizing, is the only time the brain has to catch its breath. If it doesn't, it may drown in its own biological debris... [Sleep researcher Dr. Sigrid] Veasey is learning that brain cells that don't get their needed break every night are like overworked employees on consecutive double shifts–eventually, they collapse.

Working with mice, she found that neurons that fire constantly to keep the brain alert spew out toxic free radicals as a by-product of making energy. During sleep, they produce antioxidants that mop up these potential poisons.

But even after short periods of sleep loss, 'the cells are working hard but cannot make enough antioxidants, so they progressively build up free radicals and some of the neurons die off...'

The consequences of deprived sleep, says Dr. Mary Carskadon, professor of Psychiatry and Human Behavior at Brown University, are scary, really scary."

Omega-3 and Vitamin D May Control Brain Serotonin, Research Suggests

Speaking of brain health, recent research12,13 suggests that animal-based omega-3 and vitamin D can improve cognitive function and behavior associated with certain psychiatric conditions—including ADHD, bipolar disorder, and schizophrenia—by regulating your brain's serotonin levels. As reported by ProHealth:14

"Many clinical disorders, such as autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), bipolar disorder, schizophrenia, and depression share as a unifying attribute low brain serotonin.

'In this paper, we explain how serotonin is a critical modulator of executive function, impulse control, sensory gating, and pro-social behavior,' says Dr. Patrick. 'We link serotonin production and function to vitamin D and omega-3 fatty acids, suggesting one way these important micronutrients help the brain function and affect the way we behave...'

Their paper illuminates the mechanistic links that explain why low vitamin D... and marine omega-3 deficiencies interact with genetic pathways, such as the serotonin pathway, that are important for brain development, social cognition, and decision-making, and how these gene-micronutrient interactions may influence neuropsychiatric outcomes."

The omega-3 fatty acid EPA reduces inflammatory signaling molecules in your brain that inhibit serotonin release from presynaptic neurons, thereby boosting your serotonin levels. DHA also has a beneficial influence on serotonin receptors, by increasing their access to serotonin.

According to the researchers, optimizing your vitamin D along with the animal-based omega-3 fats EPA and DHA can help optimize your brain serotonin concentrations and function, and may help prevent and/or ameliorate psychiatric symptoms without adverse side effects. Serotonin is also an immediate precursor to melatonin, which has many important health benefits, including a reduced cancer risk.

Are You Getting Enough Sleep?

The latest sleep guidelines, based on 300 studies looking at the health effects of sleep, confirm that most adults need right around eight hours of sleep for optimal health. Forty percent of American adults get only six hours of sleep or less however, and 58 percent of teens—who need anywhere from eight to 10 hours—average only seven hours or less. This kind of sleep debt is a recipe for health problems down the road, and an increased risk of dementia is just one potential side effect.

Individual sleep requirements can vary, of course, based on age, life circumstances, and health status. So how can you be sure you're getting the right amount for you? The following seven signs indicate you need to address your sleep schedule because you're not getting enough sleep:15

You're moody Chronic insomnia is associated with a greater risk for depression and anxiety,16 and even one night of insufficient sleep can have a dramatic impact on your mood. According to Lauren Hale,17 editor-in-chief of the journal Sleep Health:"If you're sleep deprived, you're more vulnerable to crankiness, irritability, and challenges coping with stress."
Your work/study performance and productivity is subpar Basic cognitive functions such as logic reasoning, focus, and even word retrieval can suffer when you're tired. According to Harvard Medical School,18 insomnia costs the American economy more than $63 billion each year in lost productivity. Sleep has also been shown to boost creative functioning and promote problem solving, both of which are valuable attributes in just about any profession.
You're gaining weight and/or developing other signs of insulin resistance or type 2 diabetes Research19,20 shows that poor sleep and/or lack of sleep can have a significant bearing on metabolic disorders such as weight gain, insulin resistance, and diabetes. Sleep exerts a marked modulatory effect on glucose metabolism, and lack of sleep will increase your risk of insulin resistance and type 2 diabetes. Shift-work, for example, has been shown to rapidly shift healthy people into a pre-diabetic state.21 Lack of sleep also decreases levels of the fat regulating hormone leptin while increasing the hunger hormone ghrelin. The resulting increase in hunger and appetite can easily lead to overeating and weight gain.22,23
Signs of sleep deprivation are showing on your face You can usually tell when someone hasn't slept well by how they look. A recent Swedish study24 looked at facial cues showing sleep deprivation, finding that people readily identified hanging eyelids, red swollen eyes, dark under-eye circles, pale skin, more wrinkles, and more droopy corners of the mouth as tell-tale signs of a poor night's sleep.
You're exhibiting poor judgment and/or lack of self-control As noted in the featured article:25

"Accurately reading social situations and making good decisions both heavily depend on the brain's capacity to process emotions. But when people are sleep deprived, the region of the brain involved with emotional processing, the prefrontal cortex, 'basically goes to sleep...'

And there's evidence being sleepy makes people sneaky, too: Sleep-deprived employees are more likely to cut corners and take credit for others work, according to research... Why? 'Presumably,' writes Jex and Britt, not getting enough Zzs results in a reduced amount of self-control."
Your libido is "missing in action" Intimacy usually falls by the wayside when you're exhausted. One recent study26,27 found that each extra hour of sleep a woman got corresponded to a 14 percent increase in the likelihood of sexual activity the following day. Those who slept more on average also reported greater vaginal lubrication during sex, compared to those who averaged less sleep.
You're drowsy during the day, and/or involuntarily fall asleep Daytime sleepiness is a clear sign that you didn't get enough sleep the night before. So, if you're constantly yawning, and/or guzzle coffee to keep yourself going, you need to head to bed earlier.

Tips for Better Sleep

Small adjustments to your daily routine and sleeping area can go a long way toward ensuring you uninterrupted, restful sleep—and thereby better health. To get you started, check out the suggestions listed in the table below. 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.

Optimize your light exposure Your pineal gland produces melatonin roughly in approximation to the contrast of bright sun exposure in the day and complete darkness at night. If you're in darkness all day long, your body can't appreciate the difference and will not optimize melatonin production. Sleep researcher Dan Pardi recommends getting at least 30 to 60 minutes of outdoor light exposure during the daytime in order to "anchor" your master clock rhythm, in the morning if possible. More sunlight exposure is required as you age.

Once the sun sets, avoid light as much as possible to assist your body in secreting melatonin, which helps you feel sleepy. It can be helpful to sleep in complete darkness, or as close to it as possible. If you need a bit of light to navigate down the hall in the wee hours of the night, install a low-wattage yellow, orange, or red light bulb. Light in these bandwidths does not shut down melatonin production in the way that white and blue light does. Salt lamps are lovely for this purpose. You can also download a free application called F.lux that automatically dims your computer device screens.28
Address mental states that prevent peaceful slumber A sleep disturbance is always caused by something, be it physical, emotional, or both. Anxiety and anger are two mental states that are incompatible with sleep. Feeling overwhelmed with responsibilities is another common sleep blocker.

To identify the cause of your wakefulness, analyze the thoughts that circle in your mind during the time you lie awake, and look for themes. Many who have learned the Emotional Freedom Techniques (EFT) find it is incredibly useful in helping them to sleep. One strategy is to compile a list of your current concerns, and then "tap" on each issue. To learn how to tap, please refer to our free EFT guide.
Keep the temperature in your bedroom below 70 degrees Fahrenheit Many people keep their homes too warm (particularly their bedrooms). Studies show that the optimal room temperature for sleep is between 60 and 68 degrees Fahrenheit.
Take a hot bath 90 to 120 minutes before bedtime This raises your core body temperature, and when you get out of the bath it abruptly drops, signaling your body that you're ready for sleep.
Avoid watching TV or using electronics in the evening, at least an hour or so before going to bed Electronic devices emit blue light, which tricks your brain into thinking it's still daytime. Normally, your brain starts secreting melatonin between 9 pm and 10 pm, and these devices may stifle that process.
Be mindful of electromagnetic fields (EMFs) in your bedroom EMFs can disrupt your pineal gland and its melatonin production, and may have other detrimental biological effects. A gauss meter is required if you want to measure EMF levels in various areas of your home. Ideally, you should turn off any wireless router while you are sleeping—after all, you don't need the Internet when you sleep.
Develop a relaxing pre-sleep routine Going to bed and getting up at the same time each day helps keep your sleep on track, but having a consistent pre-sleep routine or "sleep ritual" is also important. For instance, if you read before heading to bed, your body knows that reading at night signals it's time for sleep. Sleep specialist Stephanie Silberman, PhD suggests listening to calming music, stretching, or doing relaxation exercises.29 Mindfulness therapies have also been found helpful for insomnia.30
Avoid alcohol, caffeine, and other drugs, including nicotine Two of the biggest sleep saboteurs are caffeine and alcohol, both of which also increase anxiety. Caffeine's effects can last four to seven hours. Tea and chocolate also contain caffeine. Alcohol can help you fall asleep faster, but it makes sleep more fragmented and less restorative. Nicotine in all its forms (cigarettes, e-cigs, chewing tobacco, pipe tobacco, and smoking cessation patches) is also a stimulant, so lighting up too close to bedtime can worsen insomnia. Many other drugs can also interfere with sleep.
Use a fitness tracker to help you get to bed on time, and track which activities boost or hinder deep sleep To optimize sleep you need to make sure you're going to bed early enough. If you have to get up at 6:30am, you're just not going to get enough sleep if you go to bed after midnight. Many fitness trackers can now track both daytime body movement and sleep, allowing you to get a better picture of how much sleep you're actually getting. Newer fitness trackers like Jawbone's UP3, which should be released later this year, can even tell you which activities led to your best sleep and what factors resulted in poor sleep.

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