How Obstructive Sleep Apnea Impacts Brain Function

Obstructive sleep apnea (OSA) can damage brain function in several ways, as your airway is repeatedly blocked while sleeping and your oxygen levels drop. The consequences range from brain cell damage to reduced communication within the brain.

Low Oxygen Levels Lead to Brain Effects 

In obstructive sleep apnea, your airway gets blocked for seconds at a time throughout the night while you’re sleeping. As soon as your body detects that you’re not getting enough oxygen, you’ll wake up briefly and start breathing again.

On average, you can have anywhere from five to around 30 episodes of interrupted breathing per hour during a night. During each episode, your body, including your brain, has a low oxygen level.

Low oxygen during OSA episodes has consequences for the brain:

• Inflammation
• Oxidative damage
• Toxic chemical damage
• Altered hormone levels
• Disturbances in blood flow

All of these disruptions damage brain cells and nerve pathways, interfering with short-term and long-term brain function.

Reduced Brain Volume Can Occur 

The brain of a person with OSA can shrink in size due to nerve damage. The change, typically described as volume loss, is minimal, but it’s enough to impact brain function.

Some areas of the brain are especially affected by OSA volume loss include:

• Cerebral cortex: This is the largest part of the brain, and it controls thinking, planning, self-control, and movement.
• Hippocampus: This small area deep in the brain plays a large role in memory, as well as emotions. 
• Anterior cingulate cortex: This area of the brain is involved in regulating emotions and mediating the way you perceive and react to your emotions.
• Cerebellum: Your cerebellum is a region of the brain that helps control your balance, coordination, and movements. The communication between the cerebellum and other areas of the brain can be disrupted due to OSA.

Interrupted Sleep Affects Brain Health 

Sleep is necessary for healthy brain function. Important biological processes occur during each stage of sleep—from light sleep to deep sleep to the rapid eye movement (REM) dreaming stage. During these stages, your brain rests, recovers, heals, consolidates memory, and removes toxins.

When your sleep is interrupted due to OSA, the lack of adequate sleep has consequences:

Vascular Risk Increases

Having OSA increases your risk of conditions that can lead to a stroke. A stroke is a type of brain damage that happens due to an interruption in blood supply or bleeding in the brain. It causes a decline in brain function. 

OSA increases the risk of stroke due to an increased risk of:

• Diabetes, which damages blood vessels
• Arteriosclerosis, disease inside the blood vessels of the body
• Coronary artery disease, which is narrowing of the blood vessels in the heart
• Arrhythmia, an irregular heartbeat
• Cerebrovascular disease, which is narrowing of the blood vessels in the brain

The Brain Has Lower Connectivity

Your brain functions through rapid communication of neurons (nerve cells) throughout your brain. The connections and messages that your nerves send to each other coordinate your sensations, thoughts, action, actions, and planning.

There’s evidence that OSA can lead to slower connectivity throughout the brain. When connectivity between neurons is impaired, brain function becomes impaired.