You’d be shocked to know just all the ways that sleep apnea can harm the heart.
If you’ve ever wondered why periods of stopped breathing can be so dangerous to the cardiovascular system even though the heart doesn’t actually stop beating, you’re about to find out.
The basic premise of sleep apnea is that the cardiovascular system is subjected to ongoing periods of subnormal oxygen supply (hypoxia) in combination with labored breathing.
This duo, if left untreated, will do a big number on the heart and other body functions.
The duo leads to a chain of events. Think of the duo as a stone being dropped into a still pond, creating ripples that continuously extend outward and outward: a ripple effect.
And that’s sleep apnea. It has an incredible ripple effect on the body’s health if untreated.
If the deleterious ripple effect of sleep apnea were to be briefly summarized, it could go as follows:
The collapsed airway subjects the body to ongoing periods of:
• Abnormally low pressure within the chest/lung cavity
• Brain arousals
Consider the above the stone being dropped into the pond. The three stimuli above can then cause:
• Reduced contractile ability of the heart muscle
• Heart muscle wall stress
• Activation of the sympathetic nervous system—the “flight or fight” response
• Increase in blood pressure
• Increased heart rate
• Body-wide inflammation
• Platelet activation (aka thicker blood; higher blood clot risk)
• Impairment of the inner lining of blood vessels (endothelium)
Whew! That’s a lot! But that’s just the beginning.
For example, that impaired endothelial function can lead to increased stiffness of the arteries – which then can bring on high blood pressure throughout the day.
Now wait a minute here. If the sleep apnea ends when you awaken, why would you have high blood pressure throughout the DAY?
It all originates during sleep when you stop breathing. This drops the body’s oxygen level, arousing the brain — just enough to send signals through your nervous system to get you breathing again, but not enough to awaken you to full consciousness.
The signals instruct the blood vessels to increase the flow of oxygen to the heart and brain. However, this mechanism may carry over to after you’re awake.
The low oxygen levels (desaturation) during sleep trigger several mechanisms that persist during waking hours – ripples in the pond that continue to expand outward.
At the end of any given overnight apneic event, blood pressure may be as high as 240/130.
Sleep Apnea: Body Lying Still but Overworking
It’s one thing when your body works hard during conscious daytime exercise at the gym.
It’s a whole new, and brutal, animal when your body is overworked overnight due to stopped breathing and desaturation.
The overwork due to sleep apnea thickens the walls of the heart. That may sound like the heart gets stronger like a biceps muscle, but biceps muscle and heart muscle are not the same kind of muscle.
You do NOT want the walls of your heart to thicken. This enlargement makes the heart get less oxygen and work less effectively. Remember, an enlarged bicep is good news, but an enlarged heart is very bad news.
Furthermore, the overnight workload changes the structure of your heart. It becomes stiffer because more (and undesirable) fibrous cells grow between the cardiac muscle cells.
You Eventually Resume Breathing, Right?
So What’s the Big Deal?
Yeah, you do. But frequent bouts of hypoxia damage the blood vessels that supply oxygen to the heart.
Recurring hypoxia causes the release of substances that may cause constriction of blood vessels for hours.
And don’t assume that every actual breathing episode between the periods of stopped breathing (apneas) is normal.
Many may not be normal at all, even if you witness the sleeper’s chest/abdomen rising and falling, rising and falling.
Many of those breaths may be forced, even though you may not be able to hear or see evidence of this. The forced nature is caused by a partially collapsed airway.
Stopped breathing is caused by a completely collapsed airway.
Sleep apnea isn’t binary, in which there’s either normal breathing or stopped breathing. There can be hundreds of episodes of hypopneas: abnormal breathing.
It’s this abnormal, labored breathing that causes VERY negative or low pressures in the chest/lung cavity. This pressure is significantly low (-65 mm Hg).
However, it’s another pebble in the pond, harming the:
• Atria (heart chambers)
• Ventricles (heart chambers)
• Aorta (biggest blood vessel in the body that comes out of the heart)
When cardiac chambers are mentioned, you may think of heart failure. You’re on the right track with that thinking. Obstructive sleep apnea can lead to heart failure via several routes:
• Activating the sympathetic nervous system, including during waking hours.
• Increasing left ventricular workload, including during wakefulness.
• Increasing right ventricular workload.
All of this can then lead to atrial fibrillation, a rhythm disorder. And guess what: another ripple, in that atrial fibrillation is a major risk factor for stroke and heart attack!
Are you now getting the impression that sleep apnea’s ripples in the pond are created by a boulder?
More Stroke Triggers from Sleep Apnea
• Blood pressure swings
• Reduced blood flow to the brain
• Repeated brain arousals
• Impaired lining of blood vessel walls
• Thicker blood
If someone tells you they think you have sleep apnea, but they’re not a doctor, don’t let that stop you from SEEING a sleep doctor.
• Don’t make excuses like “I’m old.”
• Regardless of cause of OSA (obesity, smoking, narrow upper airway, old age), the damage to the body is the same, and in most cases, the treatment is the same.
Listen to the message, regardless of the messenger. If a person with NO medical training tells you that you stop breathing many times while napping or sleeping, that you snort and gasp, and points out that you nap excessively and always fall asleep reading or watching TV, then by golly, it’s time to undergo a sleep study test.