Sleep apnea is a serious disorder characterized by periods of cessation of breathing during sleep. As you sleep, neck and throat tissues relax and obstruct the flow of air, causing low blood oxygen levels and snoring. Snoring is a typical sign of sleep apnea. More specifically, the name of this disorder is obstructive sleep apnea (OSA) because it blocks the flow of air. This condition is very common in obese people, but it also occurs in those who are not obese, as in the case of people who have anatomical abnormalities that restrict the upper airway.
Symptoms of Obstructive Sleep Apnea
Most people with sleep apnea usually find out they snore from a family member or sleep partner. Because of multiple episodes of sleep disruption during the night, people usually feel tired when they wake up in the morning and may even have memory problems. If you snore and don't feel rested in the morning, you may have OSA. During periods of apnea, there are brief arousal intervals that cause interruptions in sleep without completely awakening you. You could, therefore, be unaware that apnea is occurring. Typically, people with sleep apnea snore and partially awaken gasping and choking at intervals. This vicious cycle of sleeping-gasping-waking could be occurring up to hundreds of times per night.
Effects of Sleep Apnea on the Brain and Cardiovascular System
During sleep apnea, blood oxygen levels decrease. This sudden drop in oxygen levels causes increased blood pressure and stress on the cardiovascular system. About 50% of the people who have obstructive sleep apnea develop hypertension. Over time, this increases the risk of stroke and heart failure. In fact, people with more than 20 episodes of apnea per sleep hour have a higher risk of death from abnormal heart rhythms, strokes, and heart attacks. For those who have pre-existing heart disease, recurrent episodes of decreased blood oxygen can cause sudden death.
One of the most injurious brain effects of OSA is that it disrupts sleep during stages three and four and during REM (rapid eye movement) sleep. In fact, people with severe obstructive sleep apnea may not even achieve stage three and four sleep at night. Unfortunately, these stages of sleep are essential for production of neurotransmitters such as serotonin and dopamine.
In addition to causing a decrease in cerebral oxygen levels and neurotransmitters, sleep apnea can eventually result in damage to an area of the brain known as the hippocampus, the memory and learning center of the brain. During REM sleep, memory is stored and organized. OSA has been implicated in contributing to Alzheimer's disease and other forms of dementia. As you can see, disruption of REM sleep and stages three and four sleep can wreak havoc with the brain and the body.
What can happen when there are insufficient levels of dopamine and serotonin in the brain? Start by looking at dopamine as an uplifting chemical. At sufficient levels, it helps people experience pleasurable moods. At lower levels, it's more difficult for the brain to achieve a state of happiness. Indeed, there's a greater incidence of addictions and depression in people with low dopamine levels. On the other hand, serotonin helps keep people relaxed and it enhances the quality of sleep. Appropriate balance of both chemicals is important to brain function.
Diagnosis and Treatment of Sleep Apnea
To make a definitive diagnosis, your doctor will order a polysomnogram, or "sleep study." The test is done at a sleep center where a trained health professional will monitor you through the night. The sleep study records repiratory rate, heart rate, blood oxygen, muscle movements, eye movements, and the number of apneas.
With the diagnosis in place, the treatment phase can begin. Treatment includes weight loss and sometimes using a CPAP (continuous positive airway pressure) machine at night. The machine works quietly to maintain positive airway pressure delivered via mask and tubing while you breathe. The positive pressure supports your airway, keeping it from narrowing and collapsing. Many people successfully achieve restorative sleep while using CPAP. It can be a life saver.
Cynthia Reyes - Cynthia E. Reyes, M.D. is a board certified pediatrician with 29 years of practice experience. Her writing focus is on pediatric medical ...
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