The study explores the relationship between anxiety levels in dreams and changes in plasma free fatty acids (FFA). Blood samples were collected throughout the night using an indwelling catheter. The first sample was taken at the onset of rapid eye movement (REM) sleep, a second after 15 minutes of REM, and a third 15-25 minutes after awakening. Subjects were asked to describe their dreams after being awakened. Anxiety scores from 20 dreams of nine subjects showed significant positive correlations with changes in FFA during REM sleep. No significant relationship was found between anxiety and FFA changes after awakening. The study suggests that anxiety in dreams may trigger the release of catecholamines, which mobilize free fatty acids from body fat. A previous study found a significant positive correlation between low levels of anxiety (measured by free associative speech) and plasma FFA concentrations during the waking state. No essential correlation was found between hostility and FFA concentrations. The positive correlation between anxiety and FFA raised the question of whether a similar relationship might occur during dreaming. This study was conducted to investigate this possibility. Nine male subjects aged 19-25 slept overnight in a dream laboratory. They were instructed not to eat after 6:00 p.m. and to report at 11:00 p.m. Blood samples were collected at various times during the night. The results indicate a significant relationship between anxiety in dreams and changes in plasma FFA during REM sleep. The study suggests that anxiety in dreams may trigger the release of catecholamines, which mobilize free fatty acids from body fat.The study explores the relationship between anxiety levels in dreams and changes in plasma free fatty acids (FFA). Blood samples were collected throughout the night using an indwelling catheter. The first sample was taken at the onset of rapid eye movement (REM) sleep, a second after 15 minutes of REM, and a third 15-25 minutes after awakening. Subjects were asked to describe their dreams after being awakened. Anxiety scores from 20 dreams of nine subjects showed significant positive correlations with changes in FFA during REM sleep. No significant relationship was found between anxiety and FFA changes after awakening. The study suggests that anxiety in dreams may trigger the release of catecholamines, which mobilize free fatty acids from body fat. A previous study found a significant positive correlation between low levels of anxiety (measured by free associative speech) and plasma FFA concentrations during the waking state. No essential correlation was found between hostility and FFA concentrations. The positive correlation between anxiety and FFA raised the question of whether a similar relationship might occur during dreaming. This study was conducted to investigate this possibility. Nine male subjects aged 19-25 slept overnight in a dream laboratory. They were instructed not to eat after 6:00 p.m. and to report at 11:00 p.m. Blood samples were collected at various times during the night. The results indicate a significant relationship between anxiety in dreams and changes in plasma FFA during REM sleep. The study suggests that anxiety in dreams may trigger the release of catecholamines, which mobilize free fatty acids from body fat.