A new Icelandic study finds that sleep apnea-related oxygen drops may slow the brain's ability to read emotions. Researchers say this link between hypoxia and social cognition underscores a hidden risk of disrupted sleep physiology.
The study involved 55 adults who underwent three nights of sleep monitoring. Participants completed a test requiring them to identify facial expressions at different emotional intensities.
Key findings: this group averaged a reaction time of 2.7 seconds for high-intensity emotions, but slowed to nearly 3.3 seconds for neutral faces. Recognition accuracy was high, but speed suffered significantly.
Regression analysis showed that desaturation severity was independently tied to slower responses to low-intensity emotions, with a coefficient of 363 milliseconds. Lower sleep efficiency and less REM sleep also predicted slower performance.
Importantly, the data was averaged over three nights, suggesting single-night sleep studies may miss these subtle but critical cognitive effects. The authors argue that sleep architecture is a clinically relevant marker for social cognitive performance.