The human airways allow you to speak, swallow, and breathe. They are made up of muscles and soft tissues and do not contain any bone structure that allows them to be flexible. When this passage collapses during sleep, it could be due to a loss of muscle tone, or a defect in the frame such as the accumulation of fat around the tongue or soft palate. This causes the person to choke during sleep.

Obstructive sleep apnea (OSA) is a feeling of suffocation that occurs when a lack of oxygen causes the body to repeatedly wake up and gasp to open the airway. This is a protection mechanism.

How does having OSA cause high blood pressure?

Many researchers have identified sleep apnea as a factor for high blood pressure. When there are low levels of oxygen in the body, the autonomic and hormonal nervous system that is responsible for controlling BP is activated. Blood vessels begin to narrow and other body changes occur that lead to high blood pressure.

Almost half of those with OSA develop hypertension. This link is so strong that it led the Joint National Committee on High Blood Pressure to cite sleep apnea as a cause of secondary hypertension.

Empirical evidence linking OSA to hypertension

A study published in the New England Journal of Medicine found that middle-aged adults who were not treated for obstructive sleep apnea had a 2 to 3 times higher risk of having high blood pressure over an 8-year period.

A Canadian study found that for each episode of sleep apnea that occurred per hour, the probability of developing hypertension also increased by 1%. In addition, for every 10 percent drop in oxygen levels during the night, the percentage of hypertension increased by 13 percent. Additionally, this sleep heart health study found that in severe cases of OSA, the systolic and diastolic blood pressure readings were higher, and consequently, the nocturnal blood pressure. The increase in elevated BP was proportional to the severity and presence of OSA. These individuals also had higher blood pressure levels during the day.

How does OSA treatment reduce the risk of developing hypertension?

The use of continuous positive airway pressure to treat OSA has a positive effect in reducing the risk of developing hypertension. In CPAP therapy, gentle currents of air are pumped into the airways, preventing them from collapsing during sleep. Many research studies have shown that people with moderate to severe sleep apnea who are treated with nasal CPAP had lower blood pressure readings during the night and during the day.

In a multi-center HIPARCO trial study, patients with OSA and high blood pressure who did not respond to conventional treatment received CPAP therapy for 12 weeks. This caused a 24-hour reduction in mean and diastolic blood pressure. It also improved blood pressure patterns during the night. Use of the CPAP machine for 4 hours each night is required to achieve a significant decrease in BP levels.

What are the benefits of using CPAP in hypertension?

The use of CPAP leads to a reduction in BP in all patients, regardless of whether they are using antihypertensive drugs. Patients who decline CPAP and are offered supplemental oxygen instead do not experience the same benefits as those who use CPAP.

The use of CPAP effectively reduces symptoms and comorbidities related to sleep apnea, such as type 2 diabetes and heart disease.

If you experience high blood pressure levels and cannot sleep soundly, you should visit a qualified sleep doctor to rule out sleep apnea.