WHAT IS SLEEP APNEA
Sleep Apnea is a common but under-diagnosed sleep disorder. There are several forms of sleep apnea, obstructive, central, and complex. The common belief that sleep apnea only affects the overweight, older population is inaccurate. Sleep apnea is determined by the upper airway anatomy so people that are young and/or are of normal weight can still be diagnosed with significant sleep apnea. Most doctors and therapists can pick an OSA sufferer just by looking at them. Elongation of the soft palate, enlarged tongue, retrognathia (undershot jawline), large neck circumference, brachycephalic (head is wider than it is longer) and nasal physiology are all strong anatomical indicators. The other misconception is that being overweight causes sleep apnea which is not the case. Genetics will come into it but sleep apnea leads to weight gain due to the fragmented sleep quality which in turn exacerbates the severity of sleep apnea. Even with weight loss you will still have some element of sleep apnea although it may not require treatment.
CAUSE
Sleep apnea occurs during sleep because of upper airway obstructions that can lead to snoring and the cessation of breathing. When we breathe, air flows through the windpipe and into the lungs. The narrowest part of this path is the back of the throat. When we are awake, muscle tone holds open the airway allowing normal breathing. The human airway is composed of collapsible walls of soft tissue. As we go to sleep, the muscles relax reducing the ability for the airway to stay open. The tongue, shape of the soft palate, nasal passage, and the soft tissue will contribute to the blockage at the back of the throat preventing normal breathing. An apnea episode is defined by greater than 90% blockage to the airway.
INDICATORS & SYMPTOMS
Listed are symptoms that are linked to sleep apnea but even if you have several of these, it does not mean you have apnea.
Symptoms during the night
- Waking consistently with a sore or very dry throat
- Snoring
- Witnessed apneas or irregular breathing during sleep (gasping, long pauses, etc – a spouse or partner notice these)
- Waking gasping or choking
- Restless sleep
Symptoms due to sleep disruption caused by sleep apnea
- May have periods of sleepiness or for women, it is more feelings of fatigue
- Impaired concentration & short term memory
- Morning headaches
- Sexual dysfunction
- Weight gain
- Anxiety + mood disorders
- Relationship damage
Accidents due to fatigue and lack of concentration
- Motor Vehicle
- Workplace
- Heavy machinery and tools
- Home-based
- Cooking
HEALTH CONSEQUENCE
- Hypertension
- Nocturia (frequent urination during the night)
- Stroke
- Heart disease
- Diabetes type 11
- Depression and anti-social behaviour
- Hypothyroidism (low level of thyroid hormone)
Hypopnea
Hypopnea is shallow breathing defined by 50% to 90% of obstruction of the airway. You can have high level of hypopnea without apnea events. This can be indicative of a nasal compromise. Factors such as polyps, narrow nasal passage, allergies, and a deviated septum can determine the level of hypopnea. Snoring is a strong indicator of both hypopnea and apnea due to the narrowed passages. The louder the snoring, the greater the closure
Central Sleep Apnea
Central Sleep Apnoea (CSA) is much less common than Obstructive sleep apnoea but can be more difficult to treat and in combination with other conditions, can be more dangerous. In both obstructive and central apnea the patient experiences disrupted breathing however in Central Sleep Apnoea the airways remain open. The cessation of breathing is due to a malfunctioning of the central nervous system (brain centre) which co-ordinates breathing. In simple terms, the brain delays a message to the breathing mechanism. This results in a rise in C02 and a reduction in oxygen levels.
CSA is seen in people with brain injuries, stroke, heart disease, neurological diseases, Obesity, and narcotic drugs or abuse which interfere with the receptors in the brain. There is however difficult to explain cases of CSA in individuals without any known related cause. This is called idiopathic Central apnoea
Symptoms are similar to OSA due to sleep arousals and oxygen deprivation. Treatment, if prescribed, can be CPAP or in non-responsive cases, Bilevel, Adaptive servo-ventilation, or where these fail, supplemental nocturnal oxygen. Studies are ongoing with pharmacological options.
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) occurs during sleep because of upper airway obstructions that can lead to snoring and the cessation of breathing. When we breathe, air flows through the windpipe and into the lungs. The narrowest part of this path is the back of the throat. When we are awake, muscle tone holds open the airway allowing normal breathing. The human airway is composed of collapsible walls of soft tissue. As we go to sleep, the muscles relax reducing the ability for the airway to stay open. The tongue, shape of the soft palate, nasal passage and the soft tissue will contribute to the blockage at the back of the throat preventing normal breathing. An obstructive episode is defined by greater than 90% blockage to the airway.
Now here is where it gets scary and why treatment is strongly recommended.
It is now the oxygen and heart rate that becomes the concern. Each obstruction reduces the level of oxygen and forces it to retain carbon dioxide that it would normally exhale. As a result, the body's blood gases get out of balance, and the body is subjected to a 'toxic' environment. During normal breathing, when the air that we breath reaches the lungs, the air is passed from the lungs into the small blood vessels by the pumping of the heart. This oxygenated blood is distributed throughout the body to every cell and organ.
It is the brain that monitors and controls the amount of oxygen in the blood stream. It manages the breathing rate and depth. When the airways are blocked, apnea, the level of blood oxygen is reduced below acceptable levels in our system. The brain detects the lack of oxygen and send messages to breath faster and increase the heart rate. Because there is no oxygen coming into the body, the brain then releases adrenaline to wake the body and muscle tone and breathing are restored. The patient is only briefly awakened to the first stage of sleep so generally does not recall the event. Depending on the health of the individual with OSA, the oxygen level should be restored to an acceptable level above 90% until the next event occurs. If the sufferer has serious health conditions such as heart disease or stroke or is morbidly obese, then the oxygen level is not restored above 90% and instead is maintained at suboptimal levels further leading to major risk factors. Obstructions increase heart rate, raise blood pressure, and eventually blunt the body's automatic response system, resulting in increasingly longer and more severe apneas and hypopneas. An apnea can last from seconds up to over a minute. The longer the apnea occurs, the greater the impact on the heart and oxygen levels. This cycle can occur 100 times over the night with little awareness from the sufferer. The brief wake-ups that people with OSA experience cause disrupted sleep levels diminishing their overall quality of sleep. The symptoms of sleep deprivation and snoring may be what bring most people with OSA to see their physician.
Levels of sleep apnea
Not all sleep apnea requires treatment. There are varying degrees of severity and this will determine the treatment pathway.
The measurement to describe the level of sleep apnoea is called AHI. (Apnea/hypopnea index)
The higher the index, the worse the apnea.
- Normal - < 5 events per hour
- Mild - 6- 14 events per hour
- Moderate – 15 – 30 events per hour
- Severe – Greater than 30 events per hour
Mild Sleep apnea with risk factors such as heart disease, diabetes, stroke, or Neurological disorders may result in CPAP therapy being prescribed.
The Prescribed treatment for moderate or severe obstructive sleep apnea is usually CPAP therapy. Please refer to narraeconsulting.com for further information about OSA and CPAP therapy
Important to know:
It is the physical awakenings to breathe that lead to sleep deprivation resulting in the physical symptoms.
It is the cardiovascular concession caused by the adrenaline release, heart rate variability and oxygen levels that lead to impacted organ health over time