by Dr. Mercola
Science may still be discovering the mechanisms behind why sleep is so important to your health, but you have probably experienced waking up after a poor night’s sleep, feeling cranky, over-tired and mentally foggy. This is only a small fraction of the mental and physical health issues you may suffer from sleep deprivation.
Sleep is one of the important pillars of good health, equally important as healthy foods, pure water and exercise. An increasing number of studies demonstrate how sleep relates to your sleep-wake cycles and plays a central role in multiple processes that are key to your health.
On the surface, you may have suffered through bad moods and poor energy levels from lack of sleep. Chronic sleep deprivation can also lead to depression, weight gain, increased risk of diabetes and cancer and increased risk of accidents. Sleep is necessary to feel alert, be productive and creative and for optimal body functioning.
Quality sleep doesn’t often happen naturally. Bombarded with artificial light pollution, work stress and insufficient exposure to full-spectrum natural sunlight during daylight hours, you may need to make sleep a goal to enjoy the health benefits.
A study from the University Medical Center Freiburg in Germany set out to understand more about the function of sleep and the interrelationship with health disorders and treatments. Although it may appear as if sleep is an inactive state, your brain and body are actually quite busy while you’re sleeping.
Synaptic plasticity may hold one answer to the importance of sleep
Specifically, the researchers were interested in synaptic plasticity, or how the connectivity between neurons in your brain changes. Past research has demonstrated sleep has an influence on the strength of those neuronal connections.
This study looked at the overall strength of the connections between neurons and the selective strengthening that occurs as your brain learns and encodes new information, called associate plasticity. The study engaged the participation of 20 individuals to evaluate synaptic plasticity with and without sleep deprivation.
The first stage of the research involved using transcranial magnetic stimulation (TMS) to the motor cortex of the brain in order to stimulate hand movement. After just one night of sleep deprivation, the participants required less stimulation to elicit hand movement. This indicated a greater degree of neuron excitability in the brain.
This increased excitability also reduces the selective strengthening of the neurons important to learning. While the participants reacted more quickly to stimuli after deprivation, they learned more slowly. They tested the learned response by electrically stimulating a nerve in the arm immediately before administering TMS.
The expected response would have been for the relevant synapses for this movement to strengthen as the electrical stimulation mimicked the movement elicited by the TMS. It’s an elementary mechanism of memory and learning that was inhibited with sleep deprivation.
From this information, the researchers established that sleep essentially recalibrates homeostatic and associative plasticity in your brain. In other words, sleep is essential to learning adaptive behaviour at the level of your brain’s neurons.
Regions of your brain act differently after sleep deprivation
Interestingly, not all areas of the brain react in the same way to sleep deprivation. Some areas suffer from lack of sleep more than others.
Another study using brain scans studied participants after consecutive nights of no sleep and found areas of the brain involved with concentration and problem solving were especially sluggish.
The researchers were focused on better understanding how sleep impacts the rhythmic nature of psychiatric and neurodegenerative disorders. Study co-author Derk-Jan Dijk, Ph.D., of the University of Surrey, England, was quoted in Science News, saying, “We’ve shown what shift workers already know. Being awake at 6AM after a night of no sleep, it isn’t easy. But what wasn’t known was the remarkably different response of these brain areas.”
The study enrolled 33 young adults who went without sleep for 42 hours. Over this period of time, they participated in tasks measuring reaction time, memory and learning, had their melatonin levels measured to assess and track their sleep-wake cycles and underwent 12 brain scans.
The researchers found specific areas of the brain’s activity increased and decreased with the rise and fall of melatonin, such as in the hypothalamus.
However, there were other areas of the brain that continued a downward spiral of activity and ability to perform, not in harmony with the circadian rhythm, but rather driven by growing sleep debt. As you might expect, the areas of the brain that experienced reduced function controlled learning, memory and the ability to perform simple tasks.
The high cost of sleep deprivation
After reviewing the study, Chris Colwell, Ph.D., neuroscientist, psychiatry professor and sleep specialist at the University of California, Los Angeles was quoted in the New York Times, saying, “The study is the first of its kind to show markers of negatively-affected muscle fibres, skeletal systems and motor performances due to the disruption of circadian clocks, remarkably in only a few months. They found that not only did motor performance go down on tests, but the muscles themselves just atrophied and mice physically became weaker under just two months under these conditions.”
Although stress, lifestyle choices and light pollution may affect the quality of your sleep, there is also an underdiagnosed sleep disorder that may affect the quality of sleep you experience. Obstructive sleep apnea (OSA) is a sleep-related breathing disorder during which your air exchange may stop momentarily or decrease, despite your ongoing effort to breathe.
Unfortunately, you may not recognize the symptoms of OSA as they include changes to your breathing patterns while you’re sleeping. While awake, you may experience chronic drowsiness and fatigue and your sleeping partner may complain of loud snoring at night.
The economic impact on employers may be as high as $86.9 million in lost productivity each year and just under $150 billion is the economic burden of undiagnosed OSA, including lost productivity, motor vehicle accidents and workplace accidents.
Sleep deprivation linked to dementia
A lack of sleep may also increase your risk for dementia. Researchers from University of California Berkeley’s Sleep and Neuroimaging Lab discovered that a lack of sleep leaves your brain more vulnerable to proteins believed to trigger dementia.
Alzheimer’s disease has been diagnosed in almost 40 million US adults and is considered one of the more debilitating forms of dementia. This study discovered beta-amyloid, a protein associated with those who suffer from Alzheimer’s disease, aggregates in your brain when you are chronically sleep deprived. These deposits hinder your ability to sleep and thus set up a vicious cycle.
Lead author Bryce Mander, Ph.D., neuroscientist from the University of California Berkeley, was quoted in California Association UC Berkeley magazine, saying, “What was unknown was whether or not that’s just a side relationship that has nothing to do with the clinical symptoms of dementia, or if sleep disruption is part of why these toxic chemicals in the brain are causing memory loss. This is not to say that amyloid and other pathologies can’t impact memory independent of sleep. But it does suggest that part of the way it impacts memory is through sleep-dependent memory.”
Other research demonstrates that amyloid plaques, common in Alzheimer’s disease, build up more quickly in sleep deprived lab animals. A second study then discovered how sleep clears toxins from your brain while sleeping, reducing your potential risk for dementia.
© Dr. Mercola www.mercola.com
sleeping worker photo © Fizkes