Why do you sweat with bad dreams?

Sweating during bad dreams, or nightmares, is a physiological response triggered by the body's fight-or-flight reaction. When experiencing fear or anxiety in a dream, the brain activates the sympathetic nervous system, leading to increased heart rate and perspiration. This response mimics the body’s reaction to real threats, causing sweating as a way to prepare for potential danger, even if it’s just in the mind. Additionally, factors like temperature and sleep environment can also contribute to night sweats.