A common side effect of sleep apnea is memory problems. Many thought it was the result of a lack of sleep. But that may not be the case.

Jim Reynolds says sleep apnea not only zapped his energy and focus but damaged his short term memory.

"If you imagine what it's like when you go through a night without any sleep and the next day you're foggy, imagine what it’s like going through ten years of that," Reynolds said.

During sleep apnea, muscles in the throat become relaxed, cutting off the airway and constantly waking patients up.

"I would wake up in the night gasping for air," Reynolds said.

He started having trouble remembering new things.

UCLA’s Dr. Ronald Harper says it’s common among these patients.

It’s been assumed short term memory problems are caused by sleep
deprivation. But when Dr. Harper looked inside the brain he discovered much more.

The part of our brain that stores memories is called mammillary bodies. Dr. Harper found in sleep apnea patients that area had shrunk significantly.

"The left and right side are both reduced and the left side is especially
diminished in size," Harper said.

It's suspected constant oxygen loss is to blame.

Researchers want to start testing a vitamin given to alcoholics who suffer memory loss to see if it can help.

Until then, doctors say sleeping with a breathing assist machine and daily exercise is the best treatment.

"We're finding brain areas do recover especially after exercise," Harper said.

It worked for Jim.

"My sharpness during the day improved tremendously," Reynolds said.

However, his short term memory has not returned fully and he wonders if it ever will.