How Treating Sleep Apnea May Protect Your Brain and Lower Dementia Risk
University of Miami Miller School of Medicine research and patient experience at UHealth show how diagnosing and treating sleep apnea early may help protect memory, preserve brain health and reduce long‑term dementia risk.
For thousands of people, snoring, feeling tired or waking up multiple times at night feels “normal.” But these can be signs of obstructive sleep apnea, a condition that can have serious effects on brain health.
Obstructive sleep apnea occurs when breathing stops or becomes very shallow during sleep because the airway is partially blocked.
Alberto Ramos, M.D., a professor in the Sleep Medicine Division at the University of Miami Miller School of Medicine, has spent years studying how sleep apnea increases the risk of cognitive decline and dementia. His patient, 65-year-old Odalis Pereira, is a clear example of how early diagnosis and treatment can make a difference.
Why Sleep Apnea Is More Than a Sleep Problem
The story began with her husband, who was diagnosed with sleep apnea after a frightening episode of struggling to breathe while asleep. Once he started using a CPAP machine, Pereira noticed his energy and mood improve.
One day, he turned to her and said, “You snore a little. I think you need to do a sleep study.”
Pereira’s first sleep study at UHealth — University of Miami Health System’s Sleep Center showed some irregularities, but not enough to recommend treatment. Over time, her snoring worsened. When she repeated the study, Dr. Ramos diagnosed her with obstructive sleep apnea.
Learning that she could wake up as many as 20 times per hour was a revelation. She realized she wasn’t truly resting and wasn’t getting the deep, restorative sleep her body needed.
“I was sleeping seven or eight hours, but I would wake up exhausted,” Pereira recalls. “I had no energy and didn’t understand why. I’m an active person and couldn’t do my things like before.”
How Interrupted Sleep Harms Memory and Brain Health
That deep sleep is crucial for memory. Untreated sleep apnea accelerates brain changes that affect memory and cognitive function.
“Repeated apnea episodes cause drops in oxygen levels in the brain,” said Dr. Ramos, the research director of the Miller School’s sleep program. “This triggers a panic response, raising blood pressure and heart rate. Over time, this accumulated stress damages blood vessels and the brain itself.”
His most recent study, involving more than 3,000 participants, shows that sleep apnea can reduce the size of important brain areas like the hippocampus.
“The hippocampus is key for consolidating memory. We also observed changes in small blood vessels, which increase the risk of dementia and Alzheimer’s over time,” Dr. Ramos said.
Why Early Diagnosis Can Make a Lasting Difference
Early treatment can protect the brain, reduce dementia risk and improve sleep quality, just as it did for Pereira.
Dr. Ramos emphasized, “The ideal time to identify and treat these breathing problems is between 40 and 50 years old, when it’s still possible to prevent brain changes linked to years of poor-quality sleep.”
That’s why anyone experiencing symptoms such as frequent nighttime awakenings, loud snoring, morning fatigue and low energy or conditions like high blood pressure, obesity or other cardiometabolic or heart issues that increase the risk of sleep apnea should consider a sleep study. Detecting the condition early can make a huge difference for long-term health.
How CPAP Therapy Helps Protect the Brain
While there are several ways to manage sleep apnea, Dr. Ramos prescribed a CPAP machine for Pereira.
“CPAP keeps the airway open, so it doesn’t collapse during the night,” he said. “This prevents oxygen drops, avoids the panic response, reduces vascular stress and protects against cognitive changes. Sleeping without interruptions allows memories to consolidate properly.”
At first, Pereira felt some fear about using the CPAP.
“I thought, ‘Is this really giving me air?’ I wasn’t sure,” she said.
But within two weeks, she was completely accustomed to it. Today, after several years using the CPAP, Pereira has higher energy levels and more time for activities she loves, like playing pickleball.
“I love my machine. I can’t sleep without it,” she said. “Sleeping like this changed my life. People tell me I look more energetic and that’s because now I sleep well.”
Obstructive sleep apnea is a condition in which breathing repeatedly stops or becomes very shallow during sleep because the airway is partially blocked.
Repeated breathing interruptions during sleep apnea cause drops in oxygen levels in the brain, triggering stress responses that raise blood pressure and heart rate. Over time, this stress can damage blood vessels and brain tissue involved in memory and cognition.
Research involving more than 3,000 participants shows that sleep apnea is associated with changes in brain structure, including reduced size of the hippocampus and damage to small blood vessels, which can increase the risk of dementia and Alzheimer’s disease over time.
CPAP therapy uses a machine to keep the airway open during sleep, preventing breathing interruptions. This helps avoid oxygen drops, reduces vascular stress and allows uninterrupted sleep that supports healthy memory formation.
Tags: Department of Neurology, Dr. Alberto Ramos, neurology, obstructive sleep apnea, sleep, sleep apnea, sleep medicine