The Relationship Between Sleep Apnea and High Blood Pressure

April 07, 2021
5 minutes read

The new guideline of the American Academy of Sleep Medicine describes obstructive sleep apnea as a “relatively fixed” cardiovascular disease risk factor in patients with hypertension. 

It also lists obstructive sleep apnea as a cause of secondary hypertension, with resistant hypertension being one of the clinical indications.

The prevalence of osa might also increase your risk of recurrent heart attack, stroke, vascular disease, and abnormal heart rate. If you have heart disease, multiple episodes of low blood oxygen (hypoxia or hypoxemia) can lead to sudden death from an irregular heartbeat.

An article by Peppard et al. provides interesting data that suggest a causal role of sleep-disordered breathing in hypertension and consequent cardiovascular morbidity in the general population.

Another study by Stradling et al. via Pubmed assesing the connection between cardiology and sleep disorders, also concludes that OSA is an independent risk factor for diurnal hypertension, and that this has more than trivial consequences at a public health level.

The increasing link between the incidence of OSA and poor control of blood pressure is a sign of concern. If you have or suspect to suffer from obstructive sleep apnea or hypertension keep reading to learn more.

What is high blood pressure?

High blood pressure, also called hypertension, is a common health issue in which the amount of force that pumps blood through blood vessels is higher than normal. 

You can have high blood pressure or hypertension and still feel just fine. That's because high blood pressure often does not cause illness signs that are easy to see or feel.

Your blood pressure numbers and what they mean

Your blood pressure is recorded as two numbers:

  • Systolic blood pressure (the first number) – indicates how much pressure your blood is exerting against your artery walls when the heart beats.
  • Diastolic blood pressure (the second number) – indicates how much pressure your blood is exerting against your artery walls while the heart is resting between beats.

An elevated systolic or an elevated diastolic blood pressure reading may be used to make a diagnosis of high blood pressure. According to recent studies, the risk of death from heart disease doubles with every 20 mm Hg systolic or 10 mm Hg diastolic increase among the general population from age 40 to 89.

The abbreviation mm Hg means millimeters of mercury. Mercury was used in the first accurate pressure gauges and is still used in medicine today as the standard unit of measurement for pressure.

What are high blood pressure symptoms?

People with hypertension often don't have symptoms. Usually, they find out they have high blood pressure during routine checks at a doctor's office, which is a good reason to visit your doctor regularly.

If your blood pressure is extremely high, there may be certain symptoms and risk factors to look out for, including:

  • Severe headaches
  • Nosebleed
  • Fatigue or confusion
  • Vision problems
  • Chest pain
  • Difficulty breathing
  • Irregular heartbeat or heart failure
  • Blood in the urine
  • obesity
  • severe OSA

What is the treatment for hypertension?

If there's an indication of hypertension, your doctor may suggest blood pressure monitoring at different times of the day. Checking your blood pressure around the same time every day establishes a personalized baseline. It's that baseline your doctor will use to help you determine what your numbers mean.

Your doctor may also recommend ambulatory blood pressure monitoring which is accomplished with a special device that consists of a blood pressure cuff that is worn on your arm and is attached to a small recording device that you wear on your belt. You wear the ABPM device for either 24 or 48 hours, and it records your blood pressure periodically (usually at 15-minute or 30-minute intervals) throughout that period, during your routine daily activities and while you are sleeping.

So the ABPM provides your doctor with a complete record of your blood pressure for a one- or two-day period.

Additionally, the baroreflex provides a rapid negative feedback loop in which an elevated blood pressure reflexively causes the heart rate to decrease and also causes blood pressure to decrease. Decreased blood pressure decreases baroreflex activation and causes heart rate to increase and to restore blood pressure levels.

If the pressure stays high, even when you are relaxed, the doctor may suggest exercise, weight loss, changes in your diet, and, most likely, antihypertensive medications.

If left untreated, high blood pressure can lead to cardiovascular disease, leading to stroke, heart disease, and pulmonary dysfunction. 

Fortunately, patients with hypertension can manage their condition with medication and lifestyle changes to reduce cardiovascular risk and other forms of harmful health effects.

What's the relationship between high blood pressure and obstructive sleep apnea (OSA)?

Obstructive sleep apnea (OSA) is a sleep disorder that occurs when breathing is briefly and repeatedly interrupted during sleep and affects sleep quality. This upper airway constriction has been shown to increase the risk for high blood pressure and oxidative stress.

Osa patients are diagnosed with a polysomnography, a comprehensive test, also called a sleep study, used to diagnose sleep disorders. The apnea-hypopnea index (AHI) is an index used to indicate the severity of sleep apnea.

People who suffer from obstructive sleep apnoea usually report snoring, daytime sleepiness, inability to focus, and mood swings. Research indicates that people with sleep apnea also have a high prevalence of being hypertensive patients. 

Treatment of osa usually includes lifestyle changes, sleep medicine, cpap therapy.

In healthy individuals, blood pressure naturally lowers by between 10 and 20% during sleep, a phenomenon that is sometimes referred to as "blood pressure dipping." People with severe OSA experience blood pressure dips of less than 10%, which indicates a "non dipping" blood pressure pattern. These patients, called "non-dippers," may be at greater risk for cardiovascular problems. 

Research shows that high blood pressure, often referred to as the "silent killer," can cause sleep apnea or worsen breathing in patients already affected by sleep apnea. Research also suggests that sleep apnea and high blood pressure are a dangerous combination. Studies show that daytime blood pressure levels also increase with osa severity.

Sleep apnea and high blood pressure have both been linked to a significantly increased risk of severe complications, such as stroke and heart attack.

The effect of CPAP (continuous positive airway pressure) in high blood pressure

The good news is that cpap treatment for obstructive sleep apnea syndrome may aid in lowering the development of hypertension.  The effect of continuous positive airway pressure (CPAP) promotes normal breathing during sleep and has been shown to reduce blood pressure levels. CPAP is especially effective in patients with resistant hypertension, serving as a potential treatment for these high-risk patients.

A randomized controlled trial published in The Journal of the American Medical Association (JAMA) is a peer-reviewed medical journal evaluated the Effect of CPAP on Blood Pressure in Patients With Obstructive Sleep Apnea and Resistant Hypertension and concluded that among patients with OSA and resistant hypertension, CPAP treatment for 12 weeks compared with control resulted in a decrease in 24-hour mean and diastolic blood pressure and an improvement in the nocturnal blood pressure pattern. 

CPAP therapy is especially effective in patients with resistant hypertension, serving as a potential treatment for these high-risk patients.

However, although findings are promising, larger studies are needed to assess the benefits of CPAP in patients with high blood pressure. By identifying the most effective combination of treatments for patients with sleep apnea and high blood pressure, the lower patients’ risk will be for potentially serious complications.

Written by The Sleeplay Team

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