Breathing during sleep may be influencing how our brains form memories, study finds

Our breathing during sleep may be influencing how memories in our brains are being consolidated, a new study has found.

While it is known that sleep-related brain rhythms are linked with reactivation of memory contents during sleep, researchers from Germany and the UK found that these rhythms, such as oscillations and spindles, are linked to breathing.

”Our results show that our breathing and the emergence of characteristic slow oscillation and spindle patterns are linked,” said Thomas Schreiner, Department of Psychology, Ludwig-Maximilians-Universität München, Germany, and the corresponding author of the study published in the journal Nature Communications.

Sleep spindles refer to short bursts of increased brain activity during sleep.

”Although other studies had already established a connection between breathing and cognition during wake, our work makes clear that respiration is also important for memory processing during sleep,” said Schreiner.

For the study, the researchers included 20 study participants and over the course of two sessions showed them 120 images, all of them associated with certain words.

The participants then slept for around two hours in the laboratory. The brain activity over the entire duration of learning and sleeping was recorded, along with their breathing. Upon waking up, the individuals were questioned about the associations they had learned.

The researchers found that along with reactivation of content learnt prior to sleep, the ”precision of these sleep-related brain rhythms increases from childhood to adolescence and then declines again during aging.” Further, because respiration frequency also changed with age, the researchers analysed the recorded data on breathing and were able to establish a connection between the sleep-related brain activity and breathing.

As older people often struggle with sleep disorders, respiratory disorders, and declining memory function, the team said they plan to investigate if they were linked and if interventions such as CPAP masks, that help breathe unobstructed, made sense from a cognitive perspective.