What causes people to sweat at night when they are sleeping?

My daughter and finace both sweat (a lot) at night when they sleep. Is there a disorder or name for this?

What causes people to sweat at night when they are sleeping?
heat
Reply:When i was married i had an issue with this too because my wife was always cold and had to have the heater on and many blankets on the bed. where I Have to be cold in order to sleep. even in the dead of winter I keep my bedroom window open and the air conditioner on. maybe their like me and like to be cold. i CAN NOT STAND TO BE HOT.
Reply:It may be the room temperature gets hotter as the night goes on. There are also cases that this is a symptom of tuberculosis. does this happen often? Does your kid and fiance have cough and feels tired all the time. If so, have them checked.