You probably know that obstructive sleep apnea causes people to gasp, snort and snore as their sleep is interrupted by repeated stops and starts in their breathing. And you know that these mini-suffocations, which can occur dozens of times each hour, increase the risk for all kinds of serious health problems.

But you probably don’t know that sleep apnea causes permanent changes to the structure of the brain and how the brain controls blood pressure. These changes create a vicious cycle that leaves apnea patients starved for oxygen not only at night, but also during the day—particularly at times when their bodies are most in need of oxygen!

 

Though sleep apnea often is thought of as a “man’s problem,” women develop it, too…and women are at especially high risk for the dangerous nervous system changes, a new study reveals. Male or female, if you (or a loved one) have or may have sleep apnea, you need to know about this new research…

AUTONOMIC GLITCH

Participants in the new study included male and female patients who recently had been diagnosed with sleep apnea and were not receiving treatment, plus some healthy “controls” (people without sleep apnea who served as a basis of comparison).

The point of the experiment was to see how people’s bodies respond to various physical “challenges” that use different nervous system pathways to signal increased cardiovascular demand. These challenges mimic day-to-day activities, such as straining, lifting and touching something cold. Normally such challenges, like many everyday activities, cause heart rate to speed up. This is a protective response of the autonomic regulatory system (the part of the central nervous system that regulates heart rate, blood pressure, breathing, etc. without you having to think about it), sending extra blood and oxygen to cells that are in greater need.

The challenges in the experiment included a hand-grip task (squeezing an inflatable bag with one hand as hard as possible for 16 seconds)…keeping a foot in icy water for one minute…and breathing out hard with the mouth closed and nose pinched shut (similar to what happens when a person is straining over a bowel movement!).

 

Results: For all three challenges, compared with the healthy controls, the sleep apnea patients showed an impaired response—meaning that they had heart rate increases that were less pronounced and slower to kick in.

Also, in comparing male sleep apnea patients with female sleep apnea patients, the researchers found that the degree of impairment was worse in women. Take the bag-squeezing test, for example. The heart rate of women with apnea increased just 3.3% and returned to normal very quickly, whereas in healthy women, heart rate increased 5.8% and remained elevated significantly longer. For men, however, the differences between those with and without apnea were much less pronounced. Heart rate increased 7.4% in apnea patients, compared with 8.6% in healthy men…and there was only a small difference in how long it remained elevated in the two male groups.

Why such an impaired response is dangerous: An impaired response means that tissues, including sensitive brain cells, are being starved of oxygen because blood flow is inadequate. Obviously, sleep apnea patients are oxygen-deprived whenever they stop breathing during sleep—but this study shows that people with sleep apnea also often are deprived of oxygen when they are awake and during daily physical tasks, when oxygen is needed most. That’s because their nervous systems don’t do a good job of increasing heart rate as needed to meet demands at times when the body is physiologically challenged.

What’s more, this impaired response creates a vicious cycle—impaired blood flow leads to structural changes in the brain and cardiovascular system, which leads to further impaired blood flow—and so on. The worse this gets, the greater the risk may be for heart disease, high blood pressure and other chronic illnesses associated with autonomic dysfunction, the study researchers noted. While both male and female sleep apnea patients are at risk, the dangers for women may be particularly high, given their greater magnitude of autonomic response impairment—and the fact that they are less likely to be properly diagnosed in the first place.

 

Self-defense for women and men: Sleep apnea affects an estimated 28 million adults in the US, more than 80% of whom do not realize that they have the disorder. If you have been told that you snore, gasp or grunt as you sleep, or if you often feel groggy during the day even after a full night’s rest, ask your doctor about being tested for sleep apnea. Early detection and treatment can help protect against damage to the brain, cardiovascular system and other organs…and allow you to sleep better and feel better, too.

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