As it turns out, everything is connected in the human body. The thigh bone is connected to the hip bone, the heart is connected to the lungs, the hair is connected to the skin, and so on. It stands, therefore, to reason that different diseases and conditions afflicting the human body can also be connected. Diabetes is connected to retinopathy of the eye, obesity is connected to arthritis, and sleep apnea is connected to hypertension.
A Bit About Sleep Apnea
Sleep apnea is a sleep disorder characterized by episodes of no or lessened breathing during sleep. In more specific medical terms, these are moments of hypopnea where reduced oxygen is getting into the lungs, and moments of apnea, where no oxygen is getting through at all.
There are three types of sleep apnea: obstructive, central, and complex. By far the most common of these is obstructive sleep apnea (OSA). As the name suggests, OSA occurs when a blockage or obstruction of the upper airway limits or entirely stops breathing during sleep. In order to be diagnosed with OSA, you must experience at least five of these episodes within an hour, with each lasting for at least 10 seconds. The obstruction from OSA arises from the muscles of the throat temporarily relaxing a little too much and collapsing, which narrows or blocks the airways.
The symptoms of sleep apnea can include:
- Sudden gasping or choking for air during sleep
- Dry mouth after sleeping
- Headaches in the morning upon waking
- Excessive daytime sleepiness
In addition to the frustration it poses to anyone else trying to fall asleep within earshot of your snoring, OSA is associated with a number of serious complications. These complications may not be immediately noticeable (unlike the death glare from your sleep-deprived partner the next morning), but long-term can increase your risk of death four-fold.
Untreated OSA is linked with an increased risk of:
- Insulin resistance and type 2 diabetes
- Heart attack
- Atrial fibrillation
- Non-alcoholic fatty liver disease and liver scarring
- Motor vehicle accidents
In addition to the above, obstructive sleep apnea is also related to high blood pressure, also known as hypertension.
A Bit About Hypertension
Hypertension is unfortunately exceedingly common. Almost 50% of American adults have hypertension, and in the year 2020, hypertension either directly caused or contributed to over 670,000 deaths.
Though normal blood pressure can rise and fall throughout the day due to varying factors, hypertension is diagnosed when blood pressure is constantly elevated above normal. Stage 1 hypertension is defined as a systolic pressure of 130-139mmHg or diastolic pressure of 80-89mmHg, while stage 2 is a systolic reading of 140mmHg or higher, or a diastolic of 90mmHg or over.
Having hypertension comes with all sorts of problems, including increased risks of:
- Heart attack
- Heart failure
- Kidney disease
- Eye disease
- Deterioration of cognitive function, such as memory
Unlike sleep apnea, the symptoms of hypertension are much sneakier. In fact, most people will exhibit no symptoms whatsoever, even if their blood pressure reaches mortal danger levels. In some cases, hypertension can cause symptoms such as headaches, shortness of breath, and nosebleeds, but these are very non-specific symptoms.
Sleep Apnea and Hypertension Share Common Symptoms
OSA and hypertension have been found to share several common underlying factors, leading doctors to consider these two conditions to be interrelated. Possibly, treating one can help to manage the other. Research so far has uncovered observations that link OSA and hypertension, including:
- In both patients with hypertension and OSA, fluid from the lower limbs has been found to shift upwards to the neck at night. This contributes to both airway obstruction in OSA and an increase in blood pressure
- Reduced oxygen levels from OSA triggers activation of a hormone system called the renin-angiotensin-aldosterone system. The angiotensin hormone causes blood vessels to tighten, increasing blood pressure. At the same time, excessive aldosterone hormone causes swelling of the upper airway tissues, which leads to further exacerbation of OSA
- As a type of sleep disorder, it’s not surprising that OSA causes reduced sleep quality. However, impaired sleep can also be associated with an increased risk of hypertension
- Having OSA increases inflammation throughout the body, which is detrimental to the cardiovascular system, including an increased risk of hypertension
When diagnosed with either OSA or hypertension, your ENT doctor will most likely treat you for each independently. For hypertension, this is typically with prescription anti-hypertensive medications. For OSA, the main therapy is continuous positive airway pressure (CPAP), which involves wearing a mask during sleep that delivers airflow at a pressure that keeps the airways open.
However, there is a reasonable amount of evidence that treating sleep apnea has benefits for lowering blood pressure. Doctors are recognizing that patients with hypertension that are resistant to treatment can often be more effectively managed when treating concurrent OSA. One study found that CPAP therapy was able to reduce the systolic blood pressure in patients with stubborn hypertension by up to 7mmHg.
Obesity is another link connecting both OSA and hypertension. Larger neck circumference is a risk factor for OSA, as the excess weight around the airways leads to an increased likelihood that these tissues collapse during sleep. Similarly, excessive weight can account for up to 75% of the risk of developing hypertension. Engaging in a weight loss program and managing obesity can therefore do wonders for both.
Neither obstructive sleep apnea nor hypertension are desirable conditions for the human body. Both carry the risk of life-threatening complications but fortunately, both can potentially also be managed together.