There are several well-known side effects of sleep disorders like obstructive sleep apnea (OSA) such as the increased risk of developing diabetes, heart disease, high blood pressure, metabolic syndrome, and liver problems. Recent studies, however, show sleep apnea can also cause problems for the brain as well as for the heart. This entry will dig deeper into the link between memory loss and sleep apnea.
Importance of a good night’s sleep for brain health
While sleep requirements vary from one person to another, most adults will require at least 7 to 9 hours of sleep each night. In this hectic and fast-paced society, however, sleep is often hard to come by. Research shows almost 70 million adults in the United States are affected by some sort of sleep disorder. Some 7 to 19 percent say they are not getting enough sleep, while more than 40% say they fall asleep during the day at least once a month.
The importance of sleep for the human body cannot be overstated. Experts believe it is just as important as a balanced, nutritious diet and exercise. Moreover, sleep deprivation can put your health at risk. Multiple studies have identified short sleep (less than seven hours per night) as responsible for a greater risk of weight gain and higher body mass index (BMI). This is aside from the common and largely known health risks such as a weakened immune system, low sex drive, high blood pressure, and an increased risk of developing diabetes and heart disease.
The brain, along with the body’s central nervous system, never rests. During sleep, the pathway from the brain to the nerve cells (neurons) is being formed, helping your brain store new information as memory. Sleep deprivation keeps this from happening, leaving the brain exhausted and unable to do its duties efficiently.
This is why you will also find learning new things and concentrating during the day more difficult when you are sleep-deprived or you don’t get quality sleep. Subsequently, the signals that your body gets may be delayed, compromising your coordination and making you more susceptible to accidents.
Moreover, sleep deprivation affects emotional and mental states, causing mood swings, impulsive behavior, anxiety, and depression.
But how exactly can sleep apnea affect the brain?
As said earlier, the brain uses sleep as the opportunity to store new information as memory. While your body is at rest, there are lots of things going on behind the scenes. During the stages of deep sleep, the brain downloads and processes all sorts of information you have gathered throughout the day. It consolidates and categorizes all this information into short-term memory and long-term memory.
Recent research suggests the link between memory loss symptoms and sleep apnea is breathing. People with interrupted sleep due to breathing problems are inclined to lose their memory more than those who don’t have such problems.
The key to understanding the relationship between sleep apnea and memory is in the physiology and structure of sleep. When you suffer from sleep apnea, your airways collapse, causing a partial or complete blockage. This happens multiple times a night. During episodes of sleep apnea, the breathing is interrupted or stopped, compromising the flow of oxygen to the brain. The brain, however, will try to save itself and signal the body to release hormones that trigger the body’s “breathe now!” response. As a result, the body jolts, forcing the sleeper to gasp for air. Again, this happens multiple times a night.
Most of your memories are stored during the rapid eye movement (REM) stage of sleep. This is the stage where you dream. If you wake up multiple times a night, which can happen when you jolt and gasp for air, you will not reach the deep sleep state. Moreover, your brain will not get the support it needs to store new memories.
Combine that with chronic fatigue, the continuous disruption of breathing causes damage to the pathways of the brain, resulting in structural alterations that regulate blood pressure, mood, and memory. From a long-term perspective, this affects not just memory, but brain performance as well.
Due to lack of restorative sleep from not getting quality sleep and waking multiple times throughout the night, people with sleep apnea tend to experience a wide range of mental symptoms during the daytime. This includes shortened attention span, fatigue, sluggishness, moodiness, and reduced short-term recall.
Subsequently, those who suffer from sleep apnea have trouble converting short-term memories into long-term memories. Since the process of consolidating and converting memories is interrupted, memory formation becomes impaired, causing forgetfulness.
Sleep apnea and Alzheimer’s disease
Another study confirmed that people who suffer from breathing-related sleep disorders have an earlier onset of mild cognitive impairment than those who don’t. Researchers found that the damage in the brain starts in the same areas and spreads the same way in both sleep apnea and Alzheimer’s.
What’s even more alarming is that people with sleep apnea were diagnosed with mild cognitive decline ten years earlier than people who don’t have sleep apnea. Moreover, this goes the same with sleep apnea and dementia.
There is hope…
Obstructive sleep apnea can be managed or even treated, and there are multiple ways to do it. While sleep apnea changes the structure and state of the brain, there is strong evidence that treating it may return the patient’s brain chemicals back to normal levels
The American Academy of Sleep Medicine featured a study that show the positive effects of a common and popular sleep apnea treatment called Continuous Positive Airway Pressure (CPAP) therapy. That study suggests brain damage caused by obstructive sleep apnea is reversible. This was after they found that after a year of using CPAP treatment, the patients under their study saw significant (almost completely restored) restoration in their white matter, while the gray matter saw a drastic improvement in just three months of treatment.
This supports a previous study that suggests CPAP treatment, when used regularly, can alleviate the symptoms and effects of obstructive sleep apnea, almost completely.