Mostly fear. As we get near to experiencing areas of our memory or inner feelings which disturb us, rapid heartbeat and perspiration are some of the first signs. Occasionally pleasurable exenion. Idioms: in a cold sweat; no sweat; sweat blood; sweat of one’s brow; old sweat, sweat it out. ... A Guide to Dreams and Sleep Experiences
Dreams of sweat signify either that you have too many blankets on while you sleep, or that you are working out tough issues in your dreams, pushing yourself to the limit as you are working toward results. Also, this dream may be giving you the message to stop sweating the small stuff.... Strangest Dream Explanations
It could be the result of a feverish state of the dreamer. But, if not a physical ailment, it is generally a positive dream that alludes to purification through hard work and bodily strength. It can also be interpreted as the fear that an aspect of your personality will be brought to light and will cause others to reject you.... The Big Dictionary of Dreams
This is evidence of some underlying fear, shame, guilt, or stress. On a social level, sweat is sometimes evidence of inner stress. This can reveal the presence of guilt or panic that betrays the person.
If you feel this may be the case in your dream, your interpretation should involve investigating secrets or issues in your waking life that you would rather keep hidden.... Complete Dictionary of Dreams
You are working to restore balance because of stress, fear, or guilt. There are both emotional and physical correlations to sweating and the appearance of sweat. However, the essential meaning assigned to sweat must connect with its most basic and primal function: to regulate the temperature of the body. We would die if this process did not operate effectively.
If you are sweating in your dream, your interpretation may uncover an unconscious message that some life experience is posing a threat to your equilibrium and balance. Heat represents a visceral reaction to perceived danger in the form of anger or aggression. Sweating represents your desire to restore balance from whatever might be the cause of those feelings of threat. Sweating also serves to rid the body of toxins, so dream-sweat may point to the presence of underlying thoughts, ideas, or behaviors that are ultimately poisoning your sense of well- being.... Complete Dictionary of Dreams