It's not easy to go to sleep in a lab, but Ruth Lym wanted to know why she was always tired.
"My head would fall down, you know, and then I was eating sugary stuff because I knew that would wake me up," she said.
She was later diagnosed with obstructive sleep apnea. Breathing can stop for 10 to 30 seconds, which cuts off oxygen to the brain.
"I was shocked to find out that when I was asleep, my oxygen saturation was down to 68 percent," Lym said.
Lym was one of 300 women studied for sleep quality. In the report provided by the Journal of the American Medical Association, researchers found 35 percent had sleep apnea, and those with the condition had nearly double the risk of dementia.
Dr. Ashish Patel, Huntington Hospital's director of sleep medicine, says women tend to be missed because their sleep problems usually start later in life.
"Women tend to gain weight after menopause," Patel said.
Fatigue, poor concentration, lack of energy, forgetting where your keys are - many post-menopausal women shrug off these symptoms thinking they're just getting old. But research shows that's not always the case.
"The signs of sleep apnea are very similar to dementia to cognitive dysfuntion to Alzheimer's," Patel said.
Patel said the symptoms can be reversed and prevented if you get your sleep apnea treated.
Lym said her CPAP, or continuous positive airway pressure machine, is bringing healthy sleep back into her life.
"Whatever it takes to deal with using a CPAP is absolutely worth it to your life and to the lives of people who love you," she said.