When you get really hot, your body produces more fluid to cool down. This increased fluid makes the sweatier areas on your skin even wetter. When this happens, it can make you feel sweaty all over and lead to uncontrollable sweating.
Sweating at night or during sleep is caused by an area of the brain that tells other parts of the body to release extra water through the skin. These areas are called thermoreceptors, which help us know how hot our bodies are becoming so we can adjust our temperature if necessary. People who have a lot of sweat glands close to where their nose meets their forehead often experience excessive sweating at night or while they sleep because these areas are very sensitive to heat changes in general (not just from exercise). If there’s too much moisture in these regions when you’re sleeping, it can result in excessive sweating throughout the night.