Undiagnosed and untreated OSA (obstructive sleep apnea) can cause many dangerous medical issues, even death. The lack of oxygen to the brain and body caused by sleep apnea episodes can also contribute to increased chances of stroke, depression, fatigue, weight gain, irritable bowel syndrome, and type II diabetes. Many of the issues that you will read about here are things that you may have never thought had anything to do with OSA, but hopefully by the end of this you will see how everything is related.
Increased Blood Pressure
OSA episodes produce surges in systolic and diastolic pressure that keep blood pressure levels elevated while you sleep. People that do not have sleep apnea experience a decrease in blood pressure during sleep. For many, blood pressure remains elevated during the daytime when breathing is supposedly normal. This is why screening for OSA is absolutely necessary when evaluating patients with hypertension. The use of a CPAP machine has been proven to decrease nocturnal blood pressure surges.
In 1981, Dr. Rees conducted a study, which reported the high incidence of sleep breathing disorders in diabetics. Since then, researchers have been able to document the different independent associations between OSA, insulin resistance, alertness, and glucose levels. Many times treating the OSA will, in turn, control the diabetes. Determining which one is the chicken and the egg is difficult. Having OSA can lead to diabetes, but many diabetics are also obese, which can lead to OSA. Diabetics have more complicated sleep patterns, as they need to get up to use the bathroom more often than non-diabetics. Imbalances in hormone melatonin experienced by diabetics also cause irregularities in the sleep-wake cycle.
Increased Blood Sugar
People with diabetes have higher levels of HbA1c (average blood sugar level over time) than people without diabetes. When this increase occurs, the risk of heart disease increases. There is a direct link between the severity of the OSA diagnosis and the level of the blood sugar, in that the more severe apnea cases have the highest HbA1c levels and vice-versa. In addition, multiple studies have proven that when OSA is treated, blood sugar levels improve. These findings hold true regardless of factors such as obesity, age and sex.
A study presented at the American Thoracic Society 2012 International Conference showed that moderate and severe obstructive sleep apnea predicted Type 2 diabetes, and that sleep apnea was associated with HbA1c levels.
Elevated Heart Rate
OSA causes irregularities in the Sympathetic Nervous System (SNS), which causes instability in the heart rate. OSA severity can also be linked to the Parasympathetic Nervous System (PNS), as it is directly affected by the circadian system. PNS activity is higher in non-REM sleep, which is noticed in non-OSA patients, but is much more predominant in OSA patients. This suggests that the higher the PNS activity, the greater the oxygen saturation fluctuations are. To measure the time interval between heartbeats, non-invasive methods can be utilized. Changes in HRV (heart rate variability) can be monitored to help predict future problems.
Reduced Blood Oxygen
Having an extremely low level of oxygen in the blood is known as hypoxemia, which over time, leads to hypertension and diabetes. Oxygen desaturation is an immediate consequence of OSA. Patients suffering from OSA experience oxygen desaturation in addition to periods of apnea and hypopnea. During these apneic periods, patients suffering from OSA are not receiving air delivery to the body system. If a patient cannot comply with a CPAP (recommended for Oxygen saturation levels below 90%) then oxygen therapy/ administration may be an option.
Increased Fatty Acids
OSA causes increases in nocturnal FFA (free fatty acids) that may be a catalyst to an underlying heart condition. Increases in FFA can cause insulin resistance and vascular dysfunction, and repeated exposure to these increases can promote cardiovascular disease and diabetes. Many studies have shown that supplemental oxygen will prevent the FFA elevations, thus the CPAP can be utilized here as well.
OSA is associated with arterial stiffness, depending on severity in diagnosis, that adds to cardiovascular risk.
Arterial stiffness determines how quickly the pulse wave of the heart travels to the edge and then comes back. How stiff the walls are (or not) directly correlate to the blood pressure oscillation. Patients with OSA have this arterial stiffness during the daytime as well as overnight. Vascular stiffness can be increased with OSA for many reasons – changes in elastin, endothelial dysfunction, oxidative stress and/or inflammation. Endothelial dysfunction occurs when the inner lining of the blood vessels are imbalanced and can lead to hypertension, diabetes, and many associated inflammatory diseases.
*The National Commission on Sleep Disorders Research estimated that sleep apnea is probably responsible for 38,000 cardiovascular deaths yearly, with an associated 42 million dollars spent on related hospitalizations.
As stated above, OSA can cause hypoxemia and very low oxygen saturation levels, causing disrupted sleep cycles. After repeated apneic episodes, blood pressure levels are increased, causing stress to the heart. The nocturnal apneas cause cardiac disease. Even though OSA and cardiovascular disease have common risk factors, studies prove that sleep apnea increases the risk for cardiovascular disease independently of other characteristics and/or risk factors. This link is further validated by the fact the CPAP treatment is proven to reduce blood pressure and improve ventricular function. Failure to control the sleep-related breathing problems can lessen the effectiveness of treatments for heart failure and result in accelerated deterioration of heart function.
*One of the largest epidemiologic studies conducted to date, the Sleep Heart Health Study sampling 6,424 community-dwelling individuals who underwent home polysomnography, documented increased risk of coronary artery disease, congestive heart failure, and stroke among patients with severe sleep apnea.
A few Additional Facts about Sleep Apnea:
- Left untreated, sleep apnea increases one’s risk of heart attack and stroke
- 90% of those who snore exhibit sleep apnea tendencies
- Hypertension is present in approximately 50% of patients diagnosed with OSA
- Over long periods, uncontrolled sleep apnea results in memory deterioration
- Sleep apnea can cause high blood pressure, as well as heart and lung problems
- Psychiatric issues, such as anxiety and depression can result from sleep apnea
- Uncontrolled sleep apnea can lead to muscular pain and exaggerated fibromyalgia
- Drowsiness is blamed for 200-400,000 auto accidents annually, costing $50-100 billion
- Thousands of jobs are lost annually due to OSA, costing U.S. production $60 billion
At Michigan Head & Neck Institute, we exclusively offer treatment for OSA that consists of creating a custom-fit oral appliance (mouthpiece) which is comfortable and can be adjusted to meet the requirements of each patient. Each patient that chooses an oral appliance (OA) as their treatment plan will receive follow up sleep studies (either at-home or a in a sleep lab) which will ensure that the OA is positioned accordingly. There are over 100 different types of oral appliances, and Dr. Klein works with each patient to provide the best options for their specific treatment. Please visit our website for more information.