Night sweats refer to excessive sweating while you sleep. The condition is also called sleep hyperhidrosis. If you have night sweats, your pajamas and bedsheets will be drenched. An overheated room can cause you to sweat a lot,but true night sweats are due to a medical condition or treatment and not your environment. Common causes of night sweats include menopause, infections such as tuberculosis, and cancers, including lymphoma. Follow the links below to find WebMD's comprehensive coverage about the causes of night sweats, how to treat it, and much more.