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Sleep apnea is a chronic condition that occurs when people experience breathing pauses while sleeping. Since this disorder negatively affects sleep, it can lead to adverse effects for people's physical and mental health. In a new study, researchers from the University of California, Los Angeles (UCLA) School of Nursing found evidence that sleep apnea disrupts the blood flow in the brain.

For this study, the researchers used a non-invasive magnetic resonance imaging (MRI) technique known as the global blood volume and oxygen dependent (BOLD) signal to measure people's brain blood flow. The team used the whole-brain BOLD signal in people with and without obstructive sleep apnea (OSA). The procedure is typically used to analyze brain activity.

"We know there is injury to the brain from sleep apnea, and we also know that the heart has problems pumping blood to the body, and potentially also to the brain," lead researcher of the study, Paul Macey, associate dean for Information Technology and Innovations at the UCLA School of Nursing, explained according to the press release. "By using this method, we were able to show changes in the amount of oxygenated blood across the whole brain, which could be one cause of the damage we see in people with sleep apnea."

The team tested the participants as they were performing three tasks. The first one was called the Valsalva maneuver that required the participants to breathe out of a tube. The second task was a hand-grip challenge that required the participants to squeeze their hands. The last task was the cold pressor challenge in which the participants had to put their right foot in icy cold water for one minute.

The researchers found no difference in brain blood flow between the participants with OSA and the ones without during the Valsalva maneuver. When the participants performed the two other tasks, however, participants with OSA had weaker brain blood flow response. The team added that these problems were greater in women with OSA.

The team explained that during these two tasks, the high brain regions needed to process the signals from the nerves present in the hands and foot. In people with OSA, these brains areas were jeopardized and worked much slower.

"This study brings us closer to understanding what causes the problems in the brain of people with sleep apnea," concluded Macey.

The study, "Global Brain Blood-Oxygen Level Responses to Autonomic Challenges in Obstructive Sleep Apnea," was published in the journal, PLOS ONE.