Neuroscientists have been able to prove high levels of oxygen help the brain experience deep, restorative sleep for a longer period of time, which is beneficial in aiding several bodily functions. These findings could lead to future oxygen therapy protocols for people with sleep disorders and those recovering from injury or illness.
Much work has been done to study the effects of a lack of oxygen on the brain (hypoxia). But little has been done to understand how the brain responds to hyperoxia, or elevated oxygen levels. That prompted researchers from the University of Alberta to better understand what happens when you increase the available oxygen in a clinical setting.
While oxygen is critical to the proper function of many organs, the brain normally requires about 20 percent of the body’s oxygen supply, which is transported to the brain through the blood. When there is a shortage of oxygen, the body is not able to adequately metabolize glucose and convert it to energy. This leads can lead to localized injury or even brain damage depending on how long the state of hypoxia remains.
Scientists worked with naturally sleeping rats whose brain wave activity was measured by electroencephalography (EEG) to determine how they responded to oxygen availability.
"We found that when we administer oxygen, our subjects' brains switch out of active sleep and remain in a deactivated, slow-wave state the entire time," researcher Brandon Hauer said. "Slow-wave sleep seems to be especially suited to recovery for both the brain and body. This seems to be the stage where metabolites are cleared from the brain, muscles grow and proteins reform."
When the added oxygen was removed their brains started cycling back through active or rapid-eye-movement (REM) sleep. When the oxygen level was dialed back to less than normal their brains remained in active sleep.
"Interestingly, we saw a rebound effect after the brain remained in REM sleep, in which the brain reverted to slow-wave sleep for a longer duration, as if it missed out on the slow-wave sleep during the activated stage," Hauer added.
That’s why researchers are excited about the potential for oxygen therapy in a clinical setting. They believe it could be especially beneficial for those with sleep disorders.
"Oxygen therapy could be used to enhance slow-wave states during sleep to ensure that individuals who may have disrupted sleep are getting enough of the restorative, slow-wave sleep," researcher Clay Dickson said. "Of course, this has to be tested first before it could become a therapeutic reality."