By Uday Khosla, MD on Friday, 22 July 2022
Category: Blog

Sleep Apnea and Kidney Disease

Numerous risk factors can increase your chances of developing kidney disease. Some of the obvious ones include genetic problems and certain medications. However, did you know there's a link between sleep apnea and chronic kidney problems?

On their own, both problems seem completely separate and unrelated. The deeper you dive into sleep apnea and snoring, you more you see how these issues can cause kidney disease in many patients.

With that in mind, what is the link between these two seemingly unrelated conditions? 

​Sleep Apnea and Hypertension

Sleep apnea is a sleep disorder defined by difficulty breathing while you sleep. There are two different types of sleep apnea:

Of the two conditions, more research and studies have been done surrounding OSA. In fact, numerous studies and reviews have closely monitored the connection between obstructive sleep apnea and hypertension. One particular review from 2020 concluded that frequent episodes of OSA did lead to an increase in blood pressure levels, causing an increased likelihood of developing hypertension.

To quickly recap hypertension, it is the medical term for high blood pressure. This is when blood is pushed against your arteries too strongly, meaning the hard works harder than it needs to. The World Health Organization states that hypertension is diagnosed when systolic blood pressure is greater than or exceeds 140 mmHG, and diastolic blood pressure is greater than or exceeds 90 mmG on two different days.


How does sleep apnea cause hypertension?

We've mentioned that studies show a link between sleep apnea and hypertension, but how does this sleep condition lead to high blood pressure?

When you sleep, your blood pressure levels can drop by as much as 20%. This is normal and healthy as it gives your heart a rest, improving cardiovascular health. The problem with sleep apnea is that it disrupts your sleep, preventing your blood pressure from naturally dipping at night. Consequently, you have higher blood pressure levels when you sleep, which many studies have shown will lead to hypertension if the disruptions persist. As sleep apnea causes multiple sleep disruptions every night, this is one reason it leads to high blood pressure.

Moreover, obstructive sleep apnea can cause something called intermittent oxygen transport. A report from Taiwan concluded that intermittent low oxygen levels at night can activate higher blood pressure as the heart has to work harder to get more blood - and thus, more oxygen - around the body to vital organs.

The Link Between Sleep Apnea and Kidney Disease

Where does kidney disease fit into everything? Well, it comes down to two separate issues caused by sleep apnea:

High blood pressure is strongly linked to an increased risk of chronic kidney disease. To be precise, it is the second leading cause of kidney failure in the US, responsible for 26% of cases. This happens because hypertension limits your body's ability to pump blood through the vessels to key organs - including your kidneys. As a result, the blood vessels in your kidneys become damaged, meaning they no longer function correctly.

Ironically, research shows that chronic kidney disease can actually CAUSE high blood pressure in patients. Kidneys do a good job of regulating blood pressure levels. When they're damaged, your blood pressure elevates. In turn, you have a heightened risk of making your kidneys worse because of the effects of hypertension on this organ. Effectively, this triggers a very dangerous cycle.

A disruptive sleep can worsen the function of your kidneys because of melatonin - or a lack of it. According to the National Kidney Foundation, people who sleep less see faster kidney decline because their bodies stop producing ample levels of the sleep hormone melatonin. As a result, your body stops functioning correctly at night. For your kidneys, this leads to an irregular workload where they might work harder than they normally do while you sleep, causing the decline that leads to kidney disease and failure. 

How Do You Deal With Sleep Apnea & Kidney Disease?

The good news is that you can mitigate the effects of sleep apnea on your kidneys. The best way to do this is by detecting the condition as soon as possible. Here at Kidney360, we can arrange at-home sleep studies for patients. This allows us to track your nightly habits and diagnose sleep apnea.

From here, treatments can be provided to reduce the symptoms of sleep apnea, leading to better sleep every night. The most common form of treatment is a CPAP machine that helps you breathe normally and avoid obstructions in the airways. Alongside this, you should take blood pressure medication to reduce your hypertension. Studies have shown that CPAP machines can improve your blood pressure levels at night, but additional medication is needed to control these levels over the course of a day.

Controlling sleep apnea is important for multiple reasons. Primarily, it's estimated that 42% of deaths in people with sleep apnea are attributed to cardiovascular disease. Treating this condition will improve cardiovascular health by lowering your blood pressure and taking the strain off your heart while you sleep. As a knock-on effect, this can decrease the risk of developing kidney disease. Chronic kidney disease is responsible for 16.4 deaths per 100,000 people in the population. This rate increases dramatically when hypertension is present.

Conclusion

In conclusion, sleep apnea and kidney disease are closely interlinked thanks to hypertension. Obstructive sleep apnea raises blood pressure levels and can cause hypertension, which increases the likelihood of developing chronic kidney disease. Moreover, the disruptive sleep associated with sleep apnea will also cause kidney failure. It is crucial to diagnose sleep apnea as early as possible to get the right treatment for it, preventing kidney disease. If you'd like to learn more, feel free to contact us today.