The Impact of Caffeine on REM Sleep and Brain Blood Flow

A study conducted on mice by researchers from the University of California Los Angeles has found that caffeine consumption can delay the onset of REM sleep and alter blood flow to the brain. The study observed that caffeine caused mice to sleep more solidly but delayed their short nap during the latter part of their awake phase. Additionally, daily caffeine administration shifted the onset of sleep, particularly REM sleep, by up to two hours relative to the light-dark cycle. The researchers also discovered that brain blood flow was higher when the mice were awake and lower during sleep, except during periods of REM sleep when there were significant increases in brain blood flow. These findings suggest that caffeine affects sleep patterns and brain function, potentially impacting overall sleep quality.