anatomy of a stroke

May is National Stroke Awareness Month, a time to review lifestyle choices to gauge our personal risk factors for stroke. One of the key assessments we all need to make relates to how well we breathe during sleep. Do we snore or have problems breathing as we sleep?

Untreated sleep apnea and stroke may be associated, but treatment for sleep apnea can help prevent stroke.

Sleep breathing problems that raise your risk factor for stroke

Snoring

Snoring occurs when air being inhaled and exhaled through a crowded airway creates noise as a result of friction. For some people, snoring is soft and infrequent, but for many, it’s very loud and constant. Three problems arise around the continued experience of loud and constant snoring:

It may seem harmless enough, but snoring should be treated as a potential symptom so that both the snorer and their loved ones can get the most out of their nightly sleep.

Sleep apnea

If you stop breathing for 10 or more seconds during sleep, you may have sleep apnea. An official diagnosis of sleep apnea will be made for anyone who averages at leave 5 of these episodes per hour every night.

Obstructive sleep apnea (OSA)

This form of sleep apnea is the most common. It occurs as a result of faulty mechanics in the upper airway.

It could be caused by overlarge or swollen tissues such as the tongue or uvula blocking the passage of air. Another condition leading to OSA is the retention of excessive fluid and/or fatty areas in the neck which place pressure on the airway, making it difficult for air to pass through.

The collapse or blockage of tissues in this area can lead to gasping, loud snoring, insomnia, broken sleep, nightmares about not being able to breathe, and other less obvious symptoms, such as excessive daytime sleepiness, high blood pressure, morning headache, or a throat that is extremely dry, raw or sore upon awakening.

Central sleep apnea (CSA)

This form of sleep apnea is far less common but no less dangerous. It is caused by a misfiring of signals between the brain and breathing apparatus as one sleeps.

The person with CSA may lie there, not breathing as they sleep, making zero effort to breathe, until the brain notices increases in carbon dioxide in the bloodstream (which collect when there a lapse in exhalation). Then the brain signals the body to reawaken through the release of stress hormones so that breathing can be restarted consciously.

People with CSA may also gasp for air after long periods of not breathing and will experience problems with insomnia, broken sleep, nightmares, daytime fatigue, and hypertension as well.

Untreated sleep breathing disorders and stroke

As many as 90 million Americans snore to some degree. About half of all people will snore at some time in their lives. Nearly 40 percent of adult men and almost a quarter of adult women snore nightly. It can be a problem shared among family members. Aging also increases your chances of becoming a snorer.

While snoring does not necessarily indicate that someone has sleep apnea, the more severe the snoring, the more likely the snorer will also suffer from sleep apnea.

It’s estimated that 8 out of 10 people with any form of sleep apnea remain undiagnosed (and, therefore, untreated).

According to this resource from the National Stroke Foundation, “Sleep apnea can be an after effect of stroke, but can also be the cause of a first time or recurrent stroke. The condition causes low oxygen levels and high blood pressure, both of which can increase the risk of a future stroke.”

Dr. Melissa Lipford, a neurologist at the Center for Sleep Medicine at Mayo Clinic in Minnesota, conducted studies involving patients with and without OSA who also experienced a stroke.

“During an apneic episode, the body asserts an amazing amount of effort to try to open the airway and get a breath in,” Dr. Lipford reported. Unfortunately, this effort frequently fails to supply the brain with the oxygen it needs to keep the entire body and all its systems working smoothly as you sleep.

When low blood oxygen persists, the sympathetic nervous system releases surges of stress hormones which elevate blood pressure levels and lead to fluctuations in heart rate.

Over time, these ongoing and untreated conditions during sleep will lead to systemic problems with uncontrolled high blood pressure (hypertension) and a heart arrhythmia condition known as atrial fibrillation (AFib) (learn more about AFib here). Hypertension and AFib are two well-known risk factors for stroke.

Research from the New England Journal of Medicine in 2005 shows conclusive evidence that sleep apnea “is significantly associated with the risk of stroke or death from any cause, and this association is independent of other risk factors, including hypertension. Increased severity of the syndrome is associated with an incremental increase in the risk of this composite outcome.”
FAST acronym for identifying stroke onset

When you have a stroke while sleeping

The challenge with stroke comes as soon as one is observed, making stroke risks caused by sleep breathing problems even more dangerous.

A person may fall asleep early into the night, suffer a stroke, and not know it for several hours.

If more than three hours pass after the onset of stroke, the opportunity to start critical treatment using intravenous therapy to dissolve blood clots is lost, eliminating the chance to reverse the damage caused by stroke.

It’s not uncommon for people to die in their sleep, or to sustain extensive brain damage, as a result of having a stroke during the night.

If you think you have a sleep breathing problem

You might experience several of the aforementioned symptoms, or you might have been told from loved ones that you snore loudly or gasp for breath during the night as you sleep.

Don’t take these symptoms or observations lightly; ask your primary care physician to refer you for a sleep study. You can also find out more here at our sleep health forum.

Treating both snoring and sleep apnea can lead to greatly reduced risk of stroke as well as improvements in your quality of life and overall health and well being.

The American Sleep Apnea Association joins with other allies making strides to reduce stroke risk, such as the Health eHeart Alliance, Stanford Medicine (the MyHeart Counts smartphone app), and StopAFib: For Patients, by Patients.

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