Over the last several years, we have had an explosion of studies demonstrating the damage sleep apnea can do to the human brain. The most recent one from New York University was published in the journal Neurology. In this study, 2,400 people were followed over a period of years for the development of either Alzheimer’s or MCI (minimal cognitive impairment). The results were fascinating and informative. People with untreated sleep apnea developed MCI on average ten years sooner than those without sleep apnea did. They also developed Alzheimer’s five years earlier. Even more striking was the fact that those who chose to treat their sleep apnea did not experience any acceleration in developing these neurological disorders.
This is another study that demonstrates the havoc that sleep apnea can inflict on the brain. We have additional studies demonstrating the deterioration of both gray and white matter in untreated sleep apnea. Gray matter is where the body of neurons is found and makes up most of our cerebral cortex and memory processing structures such as the hippocampus. White matter contains the tracts that connect these neurons to each other and allows communication between them in the form of nerve impulses.
What is it about sleep apnea that causes this destruction? In my book Sleep Soundly Every Night, Feel Fantastic Every Day, I delve into this. One theory called oxidative stress posits that repeated drops in oxygen brought about by an obstructed airway cause the damage. Another is that inflammatory mediators released in excessive amounts, as is seen in sleep apnea, cause the damage. Finally, another theory is that fragmented sleep, because of sleep apnea, inhibits the normal housecleaning chores of eliminating neurotoxins that require deep uninterrupted sleep.
The bottom line is that untreated sleep apnea can lead to severe brain damage. Unfortunately, if untreated, it can be very subtle and frequently overlooked until it is too late. The good news is that this and other studies have repeatedly demonstrated that with treatment this can be avoided and in some cases reversed. Therefore, the take home message is that if you have sleep apnea or manifests symptoms such as snoring, poor quality sleep, excessive fatigue, or sleepiness, get it checked out. Moreover, if you have a CPAP, wear it whenever you are sleeping. Remember, we have only one brain and it cannot be replaced.