By Margarita Nahapetyan
Breathing problems while sleeping in older men have been associated with an increased risk of developing arrhythmia (abnormal heart rhythms), a large cross-sectional study has recently revealed. Other name for sleep disordered breathing is sleep apnea.
Sleep apnea is a common disorder during which a person momentarily stops breathing, or takes very short breaths, while sleeping. The number of times breathing is being interrupted within an hour, establishes the degree of the condition - a mild case involves between 5 and 15 episodes of short breaths, while a severe case involves more than 30 episodes.
These breathing interruptions disturb a person's sleep patterns by bringing down the body's ability to refresh itself and the brain's ability to consolidate memories. The disturbances also mean that the brain does not get all the oxygen it needs for a normal functioning, as well as they can result in an increased levels of blood pressure, hypertension and stroke.
For the purposes of the new study, Dr. Reena Mehra, M.D., M.S., of Case Western Reserve University School of Medicine, Cleveland, and fellow colleagues involved nearly 3,000 men who took part in a sleep study between 2003 and 2005. The experts analyzed how many times the participants had an apnea event as well as hypopnea, which is shallow breathing while people are sleeping. The investigators also accounted if there were any periods of time when levels of oxygen would drop below 90 per cent.
The results revealed that more episodes of paused or shallow breathing experienced by the participants were associated with an increased chances of them developing two kinds of arrhythmia - one situated in the atria or the upper chamber of the heart and the other one situated in the lower chamber of the ventricles.
Researchers ound that obstructive sleep apnea - the most common type of a disorder, when the airways are partially or completely blocked - was linked to irregular heartbeats caused by a problem with the lower chambers or ventricles. Lower levels of blood oxygen also turned out to be linked to this type of arrhythmia. Central sleep apnea happens when the brain does not send the body a signal to breath. In this type of sleeping disordered breathing, the participants were more likely to develop arrhythmia in the upper chambers or the atria of the heart.
The experts stress out that the more severe the condition is, the higher is the chance of developing an arrhythmia. What is more, "there also seems to be a threshold effect such that moderate-to-severe sleep-disordered breathing confers the greatest increased odds of clinically significant arrhythmias independent of self-reported heart failure and cardiovascular disease," the authors wrote.
They concluded that further investigation on the matter is needed in order to determine causality and whether aggressive treatment of sleep-disordered breathing issues could improve cardiac outcomes. Meanwhile, doctors say that lifestyle changes can sometimes be very helpful when it comes to relieving apnea symptoms, such as weight loss, avoiding alcohol consumption and giving up smoking. And in some cases, surgical procedures can help alleviate sleep apnea, though the surgeries are not always successful.
The study appears in the June 22 issue of the Archives of Internal Medicine journal. It was funded by the National Heart, Lung, and Blood Institute, an American Heart Association Scientific Development grant, an American College of Chest Physicians -- Associated Subspecialties award, and an award from the VA Office of Health Services Research and Development.