A seemingly harmless and common sleeping disorder may not be that harmless after all. A study reveals that sleep apnea, a disorder where one experiences episodes of interrupted breathing during sleep, may affect one's memory in a way that could make a person forget the most basic and most routine of tasks.

Researchers from New York University discovered the negative effects of the said sleeping disorder on one's memory, from simple daily memories to one's ability to form new spatial memories such as remembering where one placed his or her car keys, or location of a familiar place, etc. Such difficulty in remembering is also associated with Alzheimer's.

The study involved 18 participants with severe sleep apnea. They were asked to use a joystick to navigate through one of the two unique, computer-generated 3D spatial mazes. The finding yielded to longer time to complete a familiar task for those with sleep apnea. Those were the ones that took four per cent longer to complete the maze tests.

The study said that sleep apnea disrupts the rapid eye movement (REM) sleep and impairs spatial memory in humans. REM sleep is one of the five stages of sleep that a person experiences, and is beneficial in improving mind performance.

However, researchers observed a 30 per cent overnight improvement in maze completion time when sleep was aided by a continuous positive airway pressure (CPAP) machine. In a report, it said that when sleep apnea occurred in REM sleep, subjects did not experience delayed reaction times on a separate test to measure attention. "This shows that sleepiness or lack of attention were not reasons for the decline in spatial memory," the site wrote.

Andrew Varga, Clinical Instructor of Medicine in the Division of Pulmonary, Critical Care and Sleep Medicine at NYU Langone Medical Center, said, "We have shown for the first time that sleep apnea, an increasingly common medical condition, might negatively impact formation of certain memories, even when the apnea is limited to REM sleep."

"Memory loss might be an additional symptom that clinicians should look for in patients with sleep apnea" Varga says.

Untreated apnea ,aside from affecting memory, poses many threats to the body. According to the National Heart, Lung, and Blood Institute, untreated sleep apnea can:

1.    Increase the risk of high blood pressure,  heart attack, stroke, obesity and diabetes

2.    Increase the risk of, or worsen, heart failure

3.    Make arrhythmias or irregular heartbeats

4.    Increase the chance of having work-related or driving accidents

Among possible ways to manage sleep apnea is have lifestyle changes, use mouthpieces or breathing, undergo surgery, or use of devices can successfully treat sleep apnea.

The study appeared in the Journal of Neuroscience.