By Dr. Mercola
Could poor sleeping habits cause brain damage and even accelerate onset of Alzheimer's disease? According to recent research, the answer is yes on both accounts.
According to neuroscientist Dr. Sigrid Veasey, associate professor of Medicine and a member of the Center for Sleep and Circadian Neurobiology at the Perelman School of Medicine, this is the first time they've been able to show that sleep loss actually results in the loss of neurons.
A second study also suggests that if you sleep poorly, you're at increased risk for earlier onset of severe dementia.
Sleep Loss Linked to 'Massive Brain Damage'
The first study in question, published in the Journal of Neuroscience,1, 2, 3 found that sleep is necessary for maintaining metabolic homeostasis in your brain. Wakefulness is associated with mitochondrial stress, and without sufficient sleep, neuron degeneration sets in.
The research also showed that catching up on "sleep debt" on the weekend will not prevent this damage. To reach their conclusion, the researchers submitted mice to an irregular sleep schedule similar to that of shift workers.
Inconsistent, intermittent sleep resulted in a remarkably considerable, and irreversible, brain damage—the mice actually lost 25 percent of the neurons located in their locus coeruleus,4 a nucleus in the brainstem associated with arousal, wakefulness, and certain cognitive processes. As reported by Time magazine:5
"The scientists believe that when the mice slept inconsistently, their newer cells would create more sirtuin type 3, a protein meant to energize and protect the mice. But after several days of missing sleep, as a shift worker might, the protein creation fell off and cells began to die off at a faster pace."
Chronic Sleep Disruption May Trigger Alzheimer's Onset
In a similar vein, research published in the journal Neurobiology of Aging6 suggests that people with chronic sleep problems may develop Alzheimer's disease sooner than those who sleep well. According to lead author Domenico Praticò, professor of pharmacology and microbiology/immunology in the university's School of Medicine:7
"The big biological question that we tried to address in this study is whether sleep disturbance is a risk factor to develop Alzheimer's or is it something that manifests with the disease."
Using mice bred to develop Alzheimer's, the researchers exposed one group of mice to 12 hours of light and 12 hours of darkness, while another group was exposed to 20 hours of light and only four hours of darkness. This lack of darkness significantly reduced the amount of time the mice slept.
At the end of the eight-week long study, the mice that slept less were found to have significantly poorer memory. Their ability to learn new things was also impaired—despite the fact that the two groups of mice had about the same amount of amyloid plaque (a hallmark of Alzheimer's) in their brains. According to Dr. Praticò:
"[W]e did observe that the sleep disturbance group had a significant increase in the amount of tau protein that became phosphorylated and formed the tangles inside the brain's neuronal cells...
Because of the tau's abnormal phosphorylation, the sleep-deprived mice had a huge disruption of this synaptic connection. This disruption will eventually impair the brain's ability for learning, forming new memory and other cognitive functions, and contributes to Alzheimer's disease."
Since both groups of mice were bred to develop Alzheimer's but the sleep deprived group developed these dementia-related problems sooner than the others, the researchers believe that poor sleep acts as a trigger of pathological processes that accelerate the disease. The researchers concluded that "chronic sleep disturbance is an environmental risk factor for Alzheimer's disease."
Previous research, published in the journal Science,8 has also revealed your brain removes toxic waste during sleep through what has been dubbed "the glymphatic system."9, 10, 11, 12, 13 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.
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. So it's quite likely that sleep affects your brain function and your risk of degenerative diseases such as Alzheimer's in more ways than one.
Elderly Women Are Twice as Likely to Develop Alzheimer's Than Breast Cancer
Being aware of the links between sleep and Alzheimer's onset may be particularly important for women, as they are at greatest risk for the disease.14 According to the 2014 Facts and Figures report issued by the Alzheimer's Association,15 women over the age or 60 have a one-in-six chance of developing Alzheimer's—nearly double the risk of men, who have a one-in-11 chance. Even more disturbing, a woman's chance of developing Alzheimer's is twice as great as her risk of developing breast cancer!
Since there's no cure, and no truly effective treatments, taking steps to prevent Alzheimer's becomes paramount. And it seems clear that sleeping properly is one important factor to take into consideration. For more information about Alzheimer's prevention, please see my previous article "How to Prevent Alzheimer's Disease—A Neurologist Speaks Out."
How Light and Dark Affects Your Sleep
Fortunately, there are many ways to improve your sleep, thereby helping to reduce any risks to your brain health. Maintaining a natural rhythm of exposure to sunlight during the day and darkness at night is one crucial foundational component of sleeping well. This was addressed in a recent interview with Dan Pardi (@dansplanhealth), a researcher who works with the Behavioral Sciences Department at Stanford University and the Departments of Neurology and Endocrinology at Leiden University in the Netherlands.
The reason why light is important is because it serves as the major synchronizer of your master clock. This master clock is a group of cells in your brain called the suprachiasmatic nuclei (SCN). As a group, these nuclei synchronize to the light-dark cycle of your environment when light enters your eye. You also have other biological clocks throughout your body, and those clocks subsequently synchronize to your master clock.
Most people in Western societies spend the larger portion of each day indoors, which essentially puts you in a state of “light deficiency” as outdoor light is far more intense than any indoor light fixture. Meanwhile, most people are exposed to too much light in the evening, at a time when the natural light has faded.
To maintain healthy master clock timing, aim to adjust your light exposure to a more natural light rhythm, where you get bright light exposure during the day and limited blue light and bright light exposure once the sun sets. Pardi recommends getting at least 30-60 minutes of outdoor light exposure during daylight hours, in order to “anchor” your master clock rhythm. The ideal time to go outdoors is right around solar noon but any time during daylight hours is useful.
Research also shows that exposure to bright room light before bedtime suppresses melatonin production in 99 percent of individuals. This can effectively rob you of sleep by masking sleepiness, as this hormone influences what time of day or night your body thinks it is - regardless of what time the clock on the wall displays - and because it’s one of several key biochemical signals that stimulate sleep onset and maintenance.
Shift Workers Are Particularly Vulnerable to Accidents and Disease
One of the worst things you can do to disrupt your body clock is engage in regular night shift work. I realize many people may not be able to avoid night shifts once they've chosen certain professions, but it is vital to understand that when you regularly shift your sleep patterns, you are in fact seriously compromising your health and longevity—in more ways than one. For example, in a study16 of nurses, researchers from the Harvard School of Public Health revealed that a woman's risk of type 2 diabetes rises according to how many years of night-shift work she has completed. Even working a night shift periodically for three years increased diabetes risk by 20 percent, and this increased with time.
The lack of sleep, or poor sleep that comes with shift work and jobs where you're working double shifts or other erratic schedules also makes you far more vulnerable to accidents. The recent subway train accident at Chicago's O'Hare airport17 is a perfect example In this case, more than 30 people were injured, and the accident caused an estimated $6 million in property damage. . I was born and grew up in Chicago and this is the airport I regularly use. According to the Associated Press18:
"The operator of a Chicago commuter train that crashed at O'Hare International Airport acknowledged she dozed off before the accident and had also done so last month when she overshot a station platform, a federal investigator said Wednesday. Before the crash, the operator had been running trains on the nation's second-largest public transportation system for just two months.
In Monday's accident, which injured more than 30 people, she woke up only as the eight-car train jolted onto the platform and barreled up an escalator leading into the airport. The accident occurred around 3 a.m., as the driver was nearing the end of her shift. The woman had an erratic work schedule and investigators were looking to see if that played a role in her evident fatigue... [T]he operator was an extra-board employee, meaning she filled in to cover shifts for regular employees and her hours varied from one day to the next."
If you currently work nights, I would strongly suggest trying to switch your hours, or at the very least restrict your night shift duty to a couple months at a time. This will at least give your body a chance to readjust in between. If it is not possible for you to avoid working the night shift, you can somewhat counter the health effects by keeping to a schedule. By being consistent, your body's clock will eventually adjust to your sleep/wake cycle, and this is LESS damaging than if you constantly change shifts and expect your body clock to adjust.
Next, although day sleeping makes it much more challenging to create a dark environment, it is essential that you make your bedroom pitch-black, even if you're sleeping at noon, as exposure to light squelches the production of melatonin. Even the dim glow from your clock radio could be interfering with your ability to sleep -- and more importantly, your long-term health.
Other Helpful Tips to Improve Your Sleep
Besides maintaining a natural circadian rhythm, there are a number of additional ways to help improve your sleep if you're still having trouble. 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, similar to daylight. This tricks your brain into thinking it's still daytime, thereby shutting down melatonin secretion. Under normal circumstances, your brain starts secreting melatonin during something called dim light melatonin onset. If the light in your environment doesn't dim, because of multiple artificial light sources, melatonin won't be released and this affects sleep timing, quantity, and quality.
- Sleep in darkness. Remember, light can disrupt your internal clock and your pineal gland's production of melatonin. Refrain from using night-lights, cover up your clock radio, cover your windows — I recommend using blackout shades or drapes, or use an eye mask—and don't turn on a light if you have to go to the bathroom at night. You don't need to sleep in complete darkness. The intensity of light needs to be at a certain level (different levels depending on the spectrum) to suppress melatonin production. Complete darkness is probably best however.
- Keep the temperature in your bedroom no higher than 70 degrees F. Many people keep their bedrooms too warm. A reduction in core body temperature is a part of the sleep-initiation and sleep maintenance process. A room temperature that is too warm or too cool can prevent your core temperature from lowering to its ideal place for good sleep. Aim to keep your bedroom temperature between 60 to 68 degrees, and identify the best room temperature for you through trial and error.
- Take a hot bath or shower 30 min before bedtime. The hot bath increases your core body temperature, opening up the blood vessels in your limbs. When you get out of the bath, heat can leave your body easily (if the room temperature is cool), abruptly dropping your core body temperature, making you drowsy and ready for great 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 EMF's.
Sleeping Well Is Part of a Healthy Lifestyle Plan
In summary, if you want to get good sleep, you have to have properly aligned circadian rhythms. If you don’t, aspects of your waking/sleeping system will be working at the wrong time. The ramifications of this go far beyond daytime sleepiness, as the research discussed above can attest to.
So first and foremost, make sure to get daylight exposure, ideally around solar noon, for at least half an hour or more each day. A gadget that can be helpful in instances when you, for some reason, cannot get outside during the day is a blue-light emitter. Philips makes one called goLITE BLU. (You can find it on Amazon19 for less than $150.) It's a small light therapy device you can keep on your desk. Use it twice a day for about 15 minutes to help you anchor your circadian rhythm if you cannot get outdoors.
Then, in the evening, dim environmental lights and avoid the blue light wavelength. Use blue-blocking light bulbs, dim your lights with dimmer switches and turn off unneeded lights, and if using a computer, install blue light-blocking software like f.lux.20 Also keep in mind that digital alarm clocks with blue light displays could have a detrimental effect. Last but not least, when it's time to go to sleep, make sure your bedroom is very dark. I recommend installing blackout shades for this purpose. A far less expensive alternative is to use a sleep mask to avoid disrupting your melatonin production and circadian rhythm.